91' 240 is getting too much fuel - just swapped motors from 97

[mr_wizard]

I just swapped a 97 KA into my 91 240 and currently don't have the exhaust on because it was welded to my old header. I do however have my DC Sports header on, with the EGR valve and O2 sensor attached. But I don't have the emission thing (PAIR valve?) attached because it was rusted so bad I had to saw it off my old header. I'm thinking about just taking that whole thing off? Anyway, there is a 1" hole in the side of the header now where that's suppose to go, I will plug it up once I find something that fits it. Hoping that's not causing the problem... I have swapped the TPS, knock sensor, and coolant temperature sensor from my old motor.

Ok, to the problem. I can start the car and the timing is fine but it only runs for a couple seconds and doesn't get above 500 rpm. If I try and start it again it doesn't do anything at all. So I have to take out the fuel pump fuse and crank it a few times and it starts up for a second or two and dies (using the flooded fuel). Obviously it's getting flooded. So I put the fuse back in and it pretty much starts up right away, then runs for a couple seconds and dies. Back to square one. Any idea's?
Modified by mr_wizard at 11:16 AM 4/29/2006

[NISTECH]

A whole lot more info is needed seeing your have put an OBDII motor in an OBDI car. What all did you swap? in detail

[mr_wizard]

The motor came from a 97' 240sx and has just under 70k miles on it. It came with an auto transmission as well, but I took that off and put my 5-speed transmission from my car on it. I swapped my TPS (just the black box), knock sensor (that whole wire piece that comes off), the coolant temperature sensor, Fuel wire and all it's wiring, whole distributor and plug wires (forgot to mention this), O2 sensor (forgot to mention this as well, doh), and the spark plugs (since they were iridium, better plugs) all from my old motor. NEW things I have gotten for this motor are DC Sports header, Spec 2+ clutch kit, and Fidanza Flywheel. I accidently switched the fuel lines at first, but switched them back immediatley after not being able to start it a few times. I also had the plugs in the wrong order a few times, but now they are right. My EGR valve also at first wasn't connected to my header because I couldn't get it to fit properly but I managed to get that on later hoping to fix the problem. The PAIR valve is not connected, so i have a 1" hole in the side of the header but I plan on plugging that up as soon as I find something to fit it. I don't plan on using that.

I had a guy come over and take a look at it, he noticed and fixed alot of those problems I had (wrong plug order and fixed my timing)... he could get the car to idle at 900-1000rpm and fiddle with a few things in the engine bay while I tried starting it. I know it had something to do with taking the fuel pump fuse out and putting it back in... He kept saying it was getting too much gas (by looking at the plugs, and smelling it). Anyway, I paid him just to get my timing straight so I didn't ask much more of him. So now I go to start the motor and it runs for a couple seconds and it roughly idles up to 500-600 RPM and kills itself. If I go to start it again I get absolutely nothing. So I go to take out the fuel pump fuse, go to start it, and it starts up for a couple seconds... runs rough and dies. Try starting again, no start (obviously because fuel pump fuse is out, no fuel getting to motor). So I put fuel pump fuse back in... motor starts and does same thing. So I know the timing is good because we got it to run pretty much perfect, it's just flooding itself I guess. Thanks alot for your help.
Modified by mr_wizard at 11:33 PM 4/29/2006

[NISTECH]

Couple things you can do here. Hook up a fuel gauge between the filter and the injectors. Tee it in. Do a fuel pressure drop test. See if you have any leaking injectors. When you try to start it try holding the throttle partly open and see if you can keep it running at say 2000 rpm for a few minutes till it warms up some then slowly release it and see if it will stay running. If it will may have a coolant temp sensor problem reading too cold. If it wont throttle up and still wont stay running I would be suspecting air flow meter issue.

Most importantly though do the fuel leak down test with a gauge first though.

[mr_wizard]

If I give it any sort of gas it will kill it even faster. The injectors work fine because the motor ran perfect before the motor was swapped. Where do you think I could get a fuel gauge? Also, whats airflow meter? Do you think it might be something to do with my fuel pressure regulator?

[rogoman]

When you swapped the '97 motor in, you should use the '91 intake manifold, the '91 TPS, the '91 MAF, the '91 ECU, and the '91 fuel injection electrical harness.

[mr_wizard]

I didn't swap the intake manifold, but instead swapped the coolant temperature sensor, TPS, and knock sensor. Someone said entire intake manifold just to get those all in one shot but taking the intake mani off proved to be tedious so I asked again and they said I only needed those sensors.

[180fan]

wouldda been easier if you kept all your 91 parts but used the head and block from the 97.

[mr_wizard]

Are you kidding? All I had to do was swap a few parts. No way in hell I was going to take the motor completely apart like that. I have limited time, tools, and know how... The tools I have don't go much further than my socket wrench. I had trouble taking the intake mani off and gave up, you think it would be easier to swap that and EVERYTHING else on the motor except head and block? Thanks for your input though.
Modified by mr_wizard at 10:44 AM 5/1/2006

[mr_wizard]

I can't find a fuel pressure gauge anywhere. I went and bought one from Advanced Auto Parts but it ended up not fitting. Autozone nor Pep Boys has one, atleast without ordering one and waiting a few days. I got a friend to start the car today though, while I take the fuel pump fuse in and out, and got it to start pretty easy. Once it ran it would idle right at 500 RPM. I tried giving it gas and it SLOWLY, I mean SLOWLY (while flooring it about 5 seconds) gets up to about 1000-1500 RPM and after reaching that will jump up even higher very quick, but just not responsive to the gas pedal. Like say I get it up to about 1250 RPM, then I'll floor it and wait for a second or so then it will quickly (while in neutral of course) jump up to whatever RPM I let the gas pedal off at. I also noticed while running it like this the DC Sports header was red hot towards the bottom. I shut the car off and started it back up easily without messing with the fuse. I guess because it was warmed up at that point? Think I should try swapping the fuel injectors from the old motor? Or any other suggestions?

[mr_wizard]

Anyone?

[NISTECH]

wouldda been easier if you kept all your 91 parts but used the head and block from the 97.

[mr_wizard]

The old motor threw a rod. So that rod and piston were loose bouncing around inside the block at 500+ RPM. I highly doubt I could have used alot of those original parts. I think maybe if I knew how to rebuild motors, had all the right tools, the space, and time.... that may have been easier.

So not even the Nissan tech knows whats going on with my car? I guess I'm in for spending a **** load more of cash............. ****ing Awesome.

[mr_wizard]

I actually took the car out today, atleast I know my transmission runs. It started up without me having to take out the fuel pump fuse and put it back in. It sat at about 500 RPM and I sat in the street for a few minutes trying to get it up to 1000+ RPM so I could actually put it back in gear.... so I can't let it get below 1k RPM or it is a bi*** to get reved up. Anyway, after I finally got it going i would floor it in first gear and it would accelerate VERY slow and it was very loud of course without the exhaust, then I made the mistake of slowing down and it dropped back down to 500 RPM and sat there once again waiting to get the tach up so I could get it moving. Anyway, it was running very hot when I got back, a couple notch's from dangerously hot.

I made a video about 15min after I ran it, and it actually started up and idled at 1k RPM for a little bit, then I reved it a few times and it dropped back down to 500 RPM and killed itself. Keep in mind I'm trying to give it gas the whole time and it's not responding worth a ****e, but when it does it jumps up. Here's the video http://media.putfile.com/Car-47

[rogoman]

I also noticed while running it like this the DC Sports header was red hot towards the bottom. I shut the car off and started it back up easily without messing with the fuse. I guess because it was warmed up at that point? Think I should try swapping the fuel injectors from the old motor? Or any other suggestions?

If the header starts turning red hot, this means the fuel mixture is very lean. There's a good chance that you have a major vacuum leak in the intake system. Use a vacuum gauge to measure the vacuum; at idle the reading should be around 20 InHg.

[NISTECH]

So not even the Nissan tech knows whats going on with my car? I guess I'm in for spending a **** load more of cash............. ****ing Awesome.

I do know whats wrong with it and agrreed with another post that stated the obvious problem. Someone who is very skilled with 240's non the less.You have frankenstiened an OBDI control system to an engine with OBDII emission systems.

[mr_wizard]

Sorry, I'm just getting extremely impacient with this whole project. I've been using my friends parents garage doing this swap for the passed month now, and I told them it wouldn't be any longer since a few people told me it was pretty straight forward. I've been running into so many problems it's not even funny, it's starting to look like I'll never get this over with. I've invested ALOT of cash into this swap thinking it would be cheaper than paying someone to do it. It's just not going that way at all and I'm getting nowhere and out of idea's. I can't keep buying stuff trying to fix this thing because I just recently lost my job, I was kinda hoping it would be pretty straight forward, but yeah, it's not. NICO is pretty much my only resource for help on this problem,(since no mechanics want to work on a car that's had its' motor swapped, could be a bunch of things they say) and when my friends parents are wanting the car out, it's not making it too much fun . Anyway, thanks for the help guys, i apreciate it. I'll run up to Autozone and few other places tomorrow, maybe I can have them order a fuel pressure gauge and vacuum gauge? I think it what you said it was. I'll try and look again around the engine bay for some vacuum leaks or cracked hoses. Thanks again.

[mr_wizard]

Ok, so it can be 1 of 7 problems from what I've got from the people I've been talking to and the info I've gathered. Let me know what you think.

1. Faulty Coolant Temperature Sensor (from old motor, ran fine that I know of)2. Fuel Pump Filter clogged (also ran fine before the swap, that I know of)3. Fuel Injectors (the shop I bought it from said motor ran perfect)4. No Back pressure from no exhaust5. Fuel pressure regulator6. Timing (I've messed with it a bit more after I paid someone to adjust it, didn't change much)7. Vacuum leak (pretty sure my lines are ok, I think I would've noticed though, I will check again)

[mr_wizard]

Well I fiddled with a few things yesterday and people kept saying that my timing was off. Well I checked it again, having confidence in the guy I paid to correct the timing, and took the whole dist. out and turned it 2 teeth clockwise and it started (also after turning the distributor to the right place) and idled at 2k rpm, weird. So I went to drive it and it drove well, not real well, but it was driveable. It would hiccup every second or so but it accelerated alot better than it did. I was able to drive it home today and I messed with the timing some more by turning it one more tooth clockwise and it still idled at 2k rpm but I got rid of the "hiccuping" and it pulled a little better. With just turning the dist. clockwise and counter clockwise I get nothing. The idle doesn't change and it doesn't sound any different. It accelerates about like a stock civic now (no offense to you civic owners), so it should obviously be quicker than that. It's also a bit quiter as well, with it running smoother and just all around running quiter. I tried adjusting my idle control valve and it only changed about 200 rpm or so, still 800 rpm away from your normal idle. So any idea's at this point?

[Burnsey]

mine does the same thing ..... been struggling with the sohc to dohc swap ... first I had the fuel problem you are talking about and we adjusted my timing and replaced the fuel filter and that fixed it to where it would run ... my problem now is a HUGE vac leak ... I'm reading 13 and am supposed to be reading 20 on the vac gauge ... can't find my damn leak anywhere but it causes a huge powerloss like you described ... its slower than a civic period if you ask me ... anyways my MAF was also somewhat faulty and was causing the car to slug off and not rev while in gear. Now i can rev in gear but not like I am supposed to due to my huge vac leak i still have ... Anyways hope this helps ya out a lil bit? Goodluck.

[Burnsey]

also .... might wanna check your IACV (idle air controller valve) be sure its in good shape and is properly set. and ... lol ... 1 more thing .. my throttle body isn't closing all the way sometimes ... didn't know if that might be part of your high idle?

[mr_wizard]

Thanks for the suggestions man. I found out high idle was the throttle cable being on too tight. I had my exhaust welded on as well, and it runs much better now with back pressure. It ran pretty much perfect for almost a week, but I've been doing some more mods to it and now it's having acceleration issue's at 3300 RPM. I made a thread about it. Thanks again for the help though. Nisstech, you said you knew what the problem was.... no backpressure and timing was off.... you knew this right? Just wanted to keep it a secret from me....

[Burnsey]

how did you loosen the throttle cable? ... i have an s14 throttle cable on my swap ... started as an 89 sohc ... put a 92 dohc in and the s14 cable on that conversion is supposed to "make your gas pedal high" ... I'm wondering if what you experienced might be a problem with mine also? cause my throttle body where the cable attaches doesn't look right to me ... anyways the rev/acceleration issues i had also ... fixed that 1/2 way by replacing the MAF ... now its down to the HUGE vac leak anyways let me know if ya could

[mr_wizard]

There's 2 nuts you adjust where the cable runs over the intake manifold. You just move those two around until you have it as loose or as tight as you want.