Severe engine issues...a couple questions

[DMoneyTT]

This is not really a question about a 240sx as much as it is a question regarding the ka24e. My roomate drives a 1997 Nissan hardbody pickup, and he was driving home the other day, when all of a sudden the engine begins to miss badly, and barely stays running. He managed to limp it into our driveway, and then received a phone call from his mother letting him know that his Dad was going to have emergency open-heart surgery. So, I am trying to have his truck running as a Christmas present when he gets back. I had replaced the plugs, wires, distributer, pcv valve, radiator, battery, fuel filter, and water pump within the last 10,000 miles. The truck has around 150k on the odo, and I have no idea what it's maintenance has been like prior to his purchasing of it. I have checked for vacuum leaks...none. All plugs are getting a healthy spark, and the fuel pressure ckecks out okay. The truck has never missed a beat up to this point, but now it runs so badly that I tried pulling the spark plug wires one at a time to see if there was a dead cylinder, and I couldn't tell any noticeable difference in how the engine ran. I have checked the TPS and the 02 sensor is less than 30k miles old. The only stored code is a 41 (intake air temp sensor) which has been coming up since he has purchased the truck (the temp sensor wire is melted, and I haven't fixed it yet). This has never been a problem in the last 2 years. I have never seen an engine run this badly without having obvious internal damage, (i.e. broken rod, broken valves, snapped cam shaft flange) I have never seen a vacuum leak, clogged injector, or just bad gas cause such sever problems. Could there be a problem with the MAP sensor? (I believe it's part of the TB) The truck runs pretty rough throughout the rpm range but is a little better at rpms above 2500. I am beginning to fear the worst...that the timing chain might have slipped a tooth or more. I have been told that a tooth or two may not send a valve into the piston on the SOHC ka24e. It is about the only thing I can think of that would happen suddenly, and cause the engine to consistently run this badly. Is there anything else that could render a previously smooth running ka to barely being able to hold an idle or even stay running. I have a decent amount of knowledge of the VG30DETT and VG30DE, but I have very limited knowledge of ka24e specific information. I have had no luck finding a true frontier/hardbody enthusiast, so I figured that noone knows the ka24e like the 240 guys. Hope someone has some ideas that could help. This is my first post on this forum, so please don't flame me to ashes.. Thanks

Derek

[2projects2many]

I don't recall seeing a compression test done, I'd definitely go that route first, that would rule out severe chain jump. The factory chain and gears are ultra tough and capable of 300,00 plus miles, so I don't think that is your problem, however, you may have a ring problem, or head gasket problem, that should show up in this test. I know you just put wireson it, but if you chose some cheap "house brand" wire, you may have spark going to ground some where, which can be checked at night in a dark area with a spray bottle and some water. That year I believe is obdII, so the computer is controlling everything, and therefore is very intelligent, if you had a map problem it would log it and throw a light. That's all I have for now, Good Luck with it.

[180fan]

No MAP, MAFS. It's possible that the mafs has gone screwy, but thats usually accompanied by either 1. a rev limit at 2500 rpm or 2. a really weird idle that will usually die.

This is a good 1st post. Detailed and although a bit tough to read, does the job.

I would also check the compression, but to see if it's something more localized, pull the plug on the injector one at a time. See if there's a change in the idle. If one of the injectors causes the idle to change, you've found a good one, and move onto one that will NOT change the idle. If none of them do it, it's time to move on to other things.

[DMoneyTT]

Thanks for the advice. I reread my post and I agree that it was a little hard to follow. I was pretty exhausted after messing with the truck for hours. I will try to make future posts more clear and concise. The exhaust has no signs of oil or coolant, as well as no raw fuel to be seen or smelled. I have tried looking for a spark plug wire short in the dark, with no issues arrising. That was my first thought when I first heard the truck run. I pulled the plugs today, and they look perfect. A nice light chocolate brown on the porcelain part, with no oil residue or scorching to be found. This actually was very surprising to me, after having such bad running issues. I tested the spark at each plug and am getting a strong consistent blue arc. I also regapped the plugs after giving them a light cleaning (they weren't off by any significant amount... < 5%). The truck stills runs the same. I will try a compression test tomorrow after work. I know I should be looking for consistency from cylinder to cylinder more than anything else, but what should be a rough guidline for acceptable compression levels? Also, I do not have a compression tester (it's really out of the scope of the work I do) so does anyone know if Autozone or the like might have one for rent? I will call tomorrow to see. Yes, it is OBD II. Unfortunately, there is no code coming up that would point towards a particular problem. Also, there is no water/coolant in the oil. I will try dropping the oil pan to look for any engine "debris" that might give a tell-tale sign. I am about to go and try pulling injector connectors....I hope that they are not as brittle and delicate as the ones on my Z32...of course this truck=1997...my Z=1990. Hopefully I will have good news soon and can end my posting on this. Then I can start talking my roomie into swapping the KA for an SR or CA. Maybe if the KA's shot this will come sooner than he likes...(or can afford). Well, I will continue from here.. Thanks for the advise and ideas. Keep 'em coming if you think of anything else I should try. Later.

Derek

[tek747]

Yeah i got the same issues with my 95 240! It sucks, ive checked out other discussions and tried out most of the stuff on my car but it still does what it does. Just checked the injectors last night and they are all good. Im thinkinig about pulling the engine out, cause this is beginning to bug the crap out of me....... ill let you know if something comes up positve!!