Near end of my overhaul, I need help!

[Chezedik]

I have replaced and rebuilt a huge amount of the stuff on my 1991 240sx, and I can't get it to start. I would like to know if anyone has any clues or information regarding my situation. It is a manual and I bought it from a guy who was on the highway doing 90 in 4th, and hit 3rd, going for fifth. He said it drove like crap on the way home, and when he got it there, he could not start it. Thought it was a head gasket, and so removed the head, and found out it wasn't, couldn't get it back together, and so he decided to ditch it. It has 244K mi, but nearly everything is new at this point. I have done a lot of the work to fix it up and modify the car to my liking, but more appropriately I have replaced a few suspect parts. Anyways, now that I am almost finished, I cannot get it to start, I have three check engine codes:

11 - Crank Angle Sensor not reading 0 or 90 degree signals for first few seconds of cranking12 - Mass Air Flow Meter reading out of spec21 - Ignition failure in primary circuit

The manual says for code 11, check and replace CAS (inside distributor, and I have a brand new distributor), Code 12 (had on my last 240sx, replaced sensor, solved problem, but still old on this car), and Code 22 (generally held to be a Power Transistor Unit failure, replaced with a new part). I got all of these codes even after replacement of these parts. The engine was out so I am not ruling out a break in the wiring harness, but this seems VERY improbable to me, unless any of you guys knows something. However, the diagnostic procedure (as described by the FSM) for a concurrent code 11 and 21 is to check both units and then check the harness, from there replace ECM. I have replaced the PTU and CAS and still have the codes, in fact, I did not get code 12 until after replacement of the PTU. When this happened, I did not have any sort of backfires. Now for a little more on my current setup:1991 KA24DE w/ dual exhaust cams (intake side rotated 4 teeth counterclockwise), head work (.009" shaved, port-matched, new seals, 3 angle valve job), ASP Pulley, OBX Header, test pipe, 2 1/4" exhaust engine back, Swirl Valves removed, Bored Throttle Body, Counterfeit Injen intake, Removed almost every bit of vaccuum crap except the lines for SCV solenoid (although not necessary, it will prevent a check engine light), EGR, EGR BPT, and EGR Solenoid. Last line is a combo of Throttle Body/Cruise Control/Fuel Pressure Regulator. I will be installing a Jacob's ICE Pak and Megan FPR when I get it running. I have checked and I have full spark, and I have checked and rechecked distributor timing, and am sure it is correct (even though the marks on the ASP pulley are not...), the timing chain has no excess slack and no cracks, the fuel line from the filter gets hard after just two or three seconds with the battery hooked up (Is that too weak?, just need an excuse to buy a Walbro), when I crank it by hand it has GOBS of compression, and the kickback is almost enough to take your arm off if you do not do it slowly. Finally, my thinking is that I have either a problem with the MAF, which would not allow the old car to start when I had the problem on my old 1992 240sx, but that was due to rainwater getting in it, and it threw codes 12 and 55, I did not get 55 this time around, which is the finished display code, and ECU check okay (I believe). Sorry to go on for so long, but you can't help me without info. I have given info, PLEASE HELP!!! This car is making me so...

[hannibal]

You definitely know more about this than I do, but if he engaged 3rd a 90mph, he obviously overreved. I would guess its a bottom end problem, but I dont know how he could have driven it home.

[Chezedik]

Yeah, he and I thought that at first, but it was all inspected during the rebuild and the worse thing the engine had to show for 244K hard miles was some heat scored bearings and a little sludge (he used Pennzoil). But I am certain it is nothing mechanical in the motor, It spins fine and makes a ton of compression, it must be computer related. I will probably replace the MAFS, even though I did not want to unless it was Z32. But I am concerned about the ECU, since I am having both ignition codes, and almost all of the parts are new, except the coil. But I am getting mad hot spark.

[Chezedik]

Apparently this needs a bump, and I could use some suggestions.

[Chezedik]

Could cam timing be off, who else is using the 248's? How did you time the intake?

[Florida240sx]

He didn't blow head gasket or spin rod bearing?First I'd say fix the MAFS.Check all the grounds.

[Chezedik]

Running multiple ground setup, and no rod bearings and head gasket were both cool. Does that sound right for the dual 248 cam setup? It wouldn't even run on ether, which means timing has to be off. Either cam timing, or spark timing, but if you can't burn ether, there is definately something wrong. Does the dual 248 run the exhaust in stock position and intake 4 teeth counterclockwise, or does anyone know anything else? I would assume it would be true in all cases, since they must be manufactured in lots, but I have been wrong before, am I? Otherwise I have some serious issue with spark timing, I will be doing further diagnosis on Friday, but I don't mind some avenues to look down...

[fbodtrek]

If you have compression, spark and fuel, it should fire off. If it does not, you don't ahve one of the three. It may fire off and not idle, or somthing, but it WILL fire off if you have those 3 things going on.

[DjPantsSpecR]

i'm a little worried by "GOBS of compression when turned by hand" as that is exactly what a spun rod bearing feels like. If you have another 240 you can try to turn over that will definately help you figure out if you have a serious problem, because you can definately drive a 240 with a spun rod bearing, dont ask how i found out.

I have the 248/248 setup i'm not sure what you are asking. with the upper front cover off you should be able to see at least the top of the idler sprocket that connects the lower chain to the upper chain. The timing mark on that needs to be roughly in the 1 to 2 oclock position, if you are at the right tdc you will know what i mean. from there set up your exhaust side cam in the position it needs to be in and loosely install the intake side cam how it is actually supposed to be installed. then count as you move it back teeth, 1-2-3-4 then keep it there. button everything up properly and make sure your rotor is in the right place on the right dist point, and double check all your plug wires. if it still doesnt fire you need to actually do a compression test to find out other problems...

[yellow_jacket]

Does it even sound like it might fire?

Have you checked your injector pulse?

Have you tried rotating the distributor 180?

Are you sure you are not a tooth off?

[Chezedik]

No, I am not sure I do not have the cam a tooth off, yes, I have fire, Just not sure it is at the right time. That is what concerns me about the two ignition codes, and I will need to take out the old multimeter and check the harness. I have not checked injector pulse, and will use my noid tester tommorrow. Will the MAF failure cause no injector pulse? I have checked distributor time and again, and even then, I would just need to turn the cap not the whole distributor. I have not conducted a compression test yet. And yes, I am worried about gobs of compression, but not worried about a spun bearing, they are installed and correctly. I know because I did not have this problem before I took off the head, and now with a shorter head and a new cam, I am. Also, the rod bearings are notched to keep them in place, it would take some first class raping in order to move them. Has anyone had code 11 and 21 in conjunction, if so, what was your fix?

[Chezedik]

Also, it does sound like it might fire fore a second, but then just cranks, and it cranks freely, or at least it sounds like it.

[Chezedik]

Oh, and by the way trek, an engine needs three things to run, but you can't just do them whenever, so timing is just as if not more important. Food for thought.

[DjPantsSpecR]

i'll get you a picture of one first class rod bearing rape as soon as i can get a camera.

Maybe you're not telling us something like you accidently set the cams entirely wrong at first and buttoned it up. when you went to fire it it didnt work and you bent 12 valves. When you crank it over does it even sound like its cranking or does it sound like its rotating pretty freely. When my motor had 12 bent valves it still felt like it had compression when you cranked it over by hand, and when you cranked it by starter sometimes it would pop or fire but never really start.

Do a compression check! testors are either cheap or available to rent for free. you'll quickly be able to knock off this potentially expensive problem

It should also be noted that shaving a head effectively changes cam timing because it shortens the distance between the idler sprocket and the cam gears. however i think you said you just shaved .009 so it shouldnt be a big deal at all, just more food for thought

[yellow_jacket]

It sounds like you rebuilt the bottom end as well? Is this correct?

As for the timing, check the cam timing. Set the crank pulley to tdc and pull the valve cover and check the cam timing visually.

If it sounds like it might start but then just kind sputters, you may be a tooth off. Try advancing the distributor one tooth. If that doesn't work, then rotate it 180.

If you have noid lights I would definetely check for injector pulse. It would eliminate one more variable. Then I would also check for fuel pressure.

Also, did you make sure you hooked all of the ground wires back up?

[yellow_jacket]

The more I think about it, the more it sounds like you may have a break in the harness or a bad ground. There are just too many electrical gremlins for it to be just the timing off. Check the grounds and the continuity to the ecu from those pieces the ecu isn't seeing.

The car will run with no MAF.

[Chezedik]

Okay, so I am a retard, and had a realization in a dream the other day. On my cap (in this order) are the numbers stamped 1-2-4-3, and me not thinking, I took it for granted. So, that will obviously keep it from starting, but I have not tested this out yet. And no, no catostrophic engine issues like bent or broken valves. Yes, there could be electrical gremlins, but I sure hope not. But I will be taking out the old diagnositic tools, Fuel Injector/Harness Tester, Sensor Tester, Multimeter, Vacuum Tester, and Compression Tester, and find out. My money says it starts after I fix timing and maybe **** with the distributor a little bit. I do have another question though, does anyone know how the computer diagnoses either of the faults I have listed? That is to say, can an improper firing order set the ignition codes, or a MAF fault for extra unmetered air entering the engine? Any input would be great, and sorry about the extra super retard F-up, but still need help.

[Chezedik]

So, I fixed the firing order, still didn't start. I checked compression (a little worried, but maybe no reason, let me know) got the following numbers:1 - 75 2- 783 - 804 - 78And so of course I am worried about these numbers, because they are no where near spec, but keep in mind this is also a re-ring on a stock bore. But I am worried on this point because the head is shorter, and the rings are new, but they are not completely totally new since the warped head, which leaked coolant into the cylinders. So, I am worried about ring damage due to hydraulic lock. But I have been told this is nothing to worry about since it should still start the engine (just not run well), and since they are chrome-moly rings, they will take a while to set to full compression, which can take up to 15K mi. (but these are stock rings on the KA). I re-ran the codes before I installed the MAF, and did not get the code again, but instead this time I got:11, 21 and 34 (detonation sensor code). 11 and 21 did not come on until fixing distributor timing.Well the knock sensor has a break in the ground part of the harness, but I could get a reading on the other side for continuity. I could not get a reading on the positive side (white) of the knock sensor connector to the (new)subharness, I could not however get a good reading of the whole harness (from harness to to ECU connector), I was on the 200 ohm scale, but did not check on the 2K, 20K, or 200K (just realized that, sorry).I have an ASP pulley, which I was told the marks would be off on it for timing, but didn't realize exactly how much, apparently only 20' (a ton). Fixed that, but still a no start condition. I was not able to check fuel pressure, but from disconnect of battery to stiff line was almost 30 sec. and never did get get too hard to squeeze between my finger and thumb (shouldn't 60-90lbs or so, whatever the pump runs at) be harder than that? Can the potentially varnished fuel destroy the pump? Since then I have added 4gal of premium pump unleaded. Finally, the clutch pedal's height is way lower than what it should be, and I have replaced nearly everything (Clutch Master, Slave, Hose changed to stainless, new clutch pedal assist spring). Without spring, the pedal came up more properly than without it. When I try to start the car in gear, but pedal down, the car tries to move foward a little bit, and the shifter gets jambed in gear and has to be fought out of gear. No movement happens when not in gear. Can the resistance of the transmission, even in neutral keep the car from running? Well, I think that is all I found for now. I hate to be long winded, but I hate when people have two word questions and want suggestions. I want to give you the facts as I know them, before I ask for help. Now, PLEASE HELP!! Oh, yeah, BUMP.

[Chezedik]

Oh yeah, does anyone think improper cam timing can cause low compression, but no leakdown.

[Chezedik]

One more thing, I checked the injectors and injector harness, injectors click when the distributor is pulled and turned (NO LEAKS), and the harness tester blinked while being cranked (the injectors pulsed). Can a knock sensor problem cause the car not to start or to inject fuel or spark that farly advanced or retarded?

[yellow_jacket]

Where are your #1 cylinder cam lobes pointed when the crank is at TDC? At this same point, where is the rotor on the distributor pointed(which cylinder's contact)?

You really should have over 100 psi to get the motor to run. Incorrect cam timing can cause low compression as the valves will not be closed when they are supposed to and thus let air escape. If the valves are closed when doing the leak down, it would not affect the numbers.

If you can, take a picture of the cam lobes with the crank at TDC, then rotate the crank 180 and take another pic. Please tell us where the distributor rotor is pointing for each picture. This way we can check your cam timing and the distributor timing.

[Chezedik]

I am already pretty sure that the fuel pump is bad in that it takes forever for the fuel line to get hard, and when it does, I can still nearly pinch it flat. But I will take some readings, I will likely do it in a written format like before, because I do not have a digital camera.

[benemorius]

This may be nothing, but the "gobs of compression" got my attention as well. If it really does feel as if it has too much compression when turning by hand, it is possible that the cam timing is such that all valves are closed on more than one cylinder simultaneously. Long story short, this can cause low compression while on the other hand making it harder to turn manually. Just something to consider...

If you have even a bit of fuel pressure it should at least try to start. Really it's as simple as making sure all plugs are firing and all injectors are pulsing (pull the spark plugs, then crank the engine and watch for fuel misting out of the holes - and don't tell anyone I told you to do that). If so then your primary suspect is timing. If your spark/fuel is amiss, don't forget the possibility of a bad ecu.

[Chezedik]

I thought about the ECU but I don't know, haven't gotten that far in the diagnosis. I am running a test pipe and there is no fuel smell through the exhaust, the injectors are pulsing, so I am fairly sure that I am not getting fuel. I am intrigued by your comment about the valve timing though. Maybe I am not understanding, because as I turn them by hand there should be a cylinder with all valves closed often, or did you mean something else. How can I tell that is a cam timing problem, per se, because I have no leak-down.

[doohopark]

i had the same problems, if you can freely crankit by hand your cams shouldent be off, it doesnt take much to bend those valves.. check your rotor posistion at TDC, oh after i had every thing in place, i had buncha fuel in the chamber and flooded it out would not start, what i did, took all the spark plugs out disconnected the injector and cranked it for 2-3 seconds at a time for about 5 mins, let the engine sit for about 30 min, very important you throughly clean your spark plugs or get a new one before putting them in. and about 2 squarts of oil in each cylinder to make compression higher. try that and have it at WOT when you start.

[benemorius]

I didn't quite word that right. It took me a moment to find the words, but this is a much better approach to saying it:

I've never seen it happen, but it makes sense in my head that if, for instance, the exhaust cam were 180 degrees off, you would wind up with the four strokes being: intake, exhaust, pull down the piston while creating a vacuum and perhaps sucking air in past the piston rings, and push the piston back up. Basically assuming the extreme of 180 degrees off, the result would be spitting raw fuel out the exhaust and making the engine harder to turn, thus lowering compression readings due to decreased rpm. I don't know what the effects would be if it were anything other than 180 degrees off and I'm not going to think about it long enough to figure it out. The point is that all the evidence seems to suggest looking into the timing a bit more.

PS: Lack of leakdown leave bent valves pretty much out of the question. Don't know if that eases your mind any but... If you have spark and fuel then you can probably leave the ecu alone for now.

EDIT: After glancing at those compression numbers once more, I just have to ask: Did you do that right? I'm sorry but I just can't help but think that it's odd that they're so bad yet so similar. Hell, my mind is really starting to come up with some crazy stuff, but with numbers like that you might even check to make sure you don't have a rag stuffed in your intake or something. I'm leaving now. My imagination is getting carried away...

[Chezedik]

I am almost certain I need a new pump, I have ordered it and am waiting for it to get here. The fuel line does not get hard, which means the regulator must be working fine, and it is not getting fuel. Plus, there is NO fuel smell from the exhaust. As far as the low compression readings, I have been told my rings need to seat, this engine has not been ran since the rebuild. I was speaking to a friend of mine who just rebuilt his SR, he said his numbers came out that low and it took starting fluid to get it running, but within a few minutes you could 'hear' the rings setting by the improved idle. Long story short, they are moly rings, and everyone tells me it takes a while to get them working. So I think that is what I attribute the low compression numbers to. And as far as testing it, I screwed the tester in, and cranked it for 10-15 sec or whenever I got the highest reading. This was on a cold engine that I have never started. If I were getting fuel and spark and cam timing (or spark timing for that matter) were off I would get backfiring. I am not getting that. I have already found ignition timing to be off, thanks to that beautiful ASP pulley I bought (be warned, the marks are in the wrong place!). Anyway, any day now that pump will come, and I will get a few gallons of fresh fuel and try out my theory. I will keep you guys posted. And thank you for your suggestions, even if it feels like I am blowing you off, it gives me food for thought, and that helps.

[benemorius]

Sounds good, mate. I hadn't thought about the fact that the engine would be dead cold and never before run when testing the compression. Good luck and don't forget to check back in to report your success.

[Chezedik]

Well, it is going to be a hot one tommorrow, but I finally got my Walbro, so I will change it along with the FPR, maybe install the ignition system. That way I will know that the fuel system is working properly. But hey, does anyone know if a bad knock sensor can cause codes 11 21 and 34?

[Chezedik]

Okay, this is starting to get to me. I checked the distributor timing again, it was good. (at first I thought it was 180 out, but then I realized it was just on #4, stupid mistake) Fuel pump is new, still no good. I did observe a few things though:* EFI relay (green relay) is very hot to the touch, switched it out with the condensor fan relay(blue relay), it does not get hot, but the car still won't start.* With the knock sensor subharness disconnected, I get a code 34 but no codes for 11 or 21* This time when I go out there I get a code 13 (engine temp sensor), I get this code whether it is disconnected or not. I disconnected it, because I have been reading a book on Bosch fuel injection, and it says that with the unit disconnected it will act as if it is a 'cold-cold' start.*Apparently I have a leak at one of the intake manifold bolts, because it filled a small pocket with coolant. This is a very small leak however, in that I have not been to my car in weeks, and it is only leaked a teaspoon or so. I think this could probably be remedied if I were to put sealer on the bolt. It is actually in the place of where one of the studs were. I found it easier to replace the stud with a bolt for install purposes. This is probably my payback. * When I pull the plugs, they are not fuel fouled, in fact, they look brand new. This is of course save for the fact that they are wet. This time out I had fuel all over my hands from the pump, and they smelled maybe like fuel, but maybe that was my hand. In the past I have tasted the fluid, it is not antifreeze or fuel, but oil. At one time when I reinstalled the cylinder head after a rebuild, I put oil in the cylinders to lube them, and cranked it, but I did this with no plugs in the cylinders (big mess).

Can any malfunction in the Detonation sensor system cause the car not to start? I would think not, but I am at the end of my rope.

Can a broken or bad knock sensor cause codes 11 and 21?

Does anyone know how the coolant temp sensor circuit reacts to the sensor being disconnected?

Tommorrow, I may go out there and fiddle with taking off the valve cover and taking notes on the cam positions. Also, maybe install that FPR and ignition. I have been hesitant to do that since it would be adding more parts to have a problem with. But I am running out of things to do. On the plus side, I fixed the clutch pedal problem, it was just (way) incorrectly set pedal height. As usual, anything you guys can shoot my way, I would appreciate.