scottyMIz Posted June 30, 2003 Share Posted June 30, 2003 ok guys i'm stumped ever since i swapped the 83 cps into my 81 engine i have had problems.When i first put it in it ran really advance that was no prob just retarded it.Well now if you hold your foot on the gas too long it will go like hell then back off Like it's loosing power.I haven't looked at the boost to see if it's spiking yet it's hard to keep an eye on the boost gauge a/f meter and the road all at once.I'm gonna do some tests tonight but i am stumped on weather it's the turbo or the timing/ecu thing.I have the stock efi and ignition system right now.I'm planning on getting a haltech from owen but right now i don't have the cash for it so that's why i'm running the stock stuff.What i'm thinking is that the stock system for some reason is either retarding or advancing the timing when the boost hits.Like maybe the knock sensor is detecting something i'm not hearing and retarding it.I have the timing set to stock wish i could watch it under boost to see what she is doing. Little hard unless i have a dyno or i ride on the front while someone drives Which i'm not gonna do don't worry. The thinking of might be the turbo is maybe it's spiking and i'm not seeing it.I need to relocate my boost gauge to my pillar pod cuz in the dash it's hard to look from one side to the other.Anyone got any ideas? Quote Link to comment Share on other sites More sharing options...
rags Posted July 10, 2003 Share Posted July 10, 2003 100% sure it's a bad fuel pump Quote Link to comment Share on other sites More sharing options...
Afshin Posted July 10, 2003 Share Posted July 10, 2003 Well I doubt that it's the timming being retarded by the cpu causing the problem. I have had 3 diiferent 83 turbo set ups with factory system over theyears, and none of them could retard the timing that significantly when overboosted and knocking. In other words the ability of the factory CPU to retard timimg enough to avoid knocking/overboost is very very very limited. It would be nice to know what the boost is. fuel delivery is definitely a possibility as already suggested and other consideration would be leaking WG actuator and boost leak see "can't hold boost" post on this forum (James "spork" has a nice write up on checking for leaks). BTW did you do anything else at all when changing from the 81 to 83 CPU ? The 83 cpu could be faulty, but that is not so common, perhaps you could put back the 81 cpu on and see if the problem goes away, then you know it's not fuel or leak related. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 10, 2003 Share Posted July 10, 2003 Ok, so hook up your timing light and get a buddy to drive. As he floors it, pop the hood, climb up front, and check out how much the timing is moving under boost. If you aren't too dexterous, you could use a skateboard or roller blades beside the car. Seriously... I agree with the fuel system diagnosis... I'd check filter and pump voltage. Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted July 10, 2003 Author Share Posted July 10, 2003 well guys i just rode under the hood closes perfectly no really rags is right the fule pump took a dump cuz i didn't have a pre filter on it.Anyone know where i can get one that takes 1/2 inch line? Quote Link to comment Share on other sites More sharing options...
fl327 Posted July 11, 2003 Share Posted July 11, 2003 youve got me scared now, my car does the same thing and my timing is good, havent checked pump voltage yet, is the pre filter same thing as the fuel filter in the engine bay??? Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted July 11, 2003 Share Posted July 11, 2003 I think fuel pump too.... whenever it cuts out after a certain RPM it almost is always fuel starvation. By the way, since he mentioned swapping from a '81 to '83 ignition system...... I've been seeing this a lot lately, are the '81 systems so bad?? I'm putting an '81 complete engine/efi into my car next week, you guys have me worried. Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted July 11, 2003 Author Share Posted July 11, 2003 the wire harness is from an 81 but my crank position sensor was bad so i swapped in the cps from an 83 distributor and all.My old system worked fine from the 81 if the cps hadn't died i'd still be using it.Ya the prefilter is kinda like the one under the hood but goes between the pump and tank to keep the crap out.My tank had some rust in it so it ended up killing the pump took about 2 years but it did it.The 81 system is just fine don't worry about that but i think the cps from the 83 is a better unit. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted July 11, 2003 Share Posted July 11, 2003 yeah I think that's the part that everyone says is the problem, the crank position sensor. Hmmmmmm is this a hard/expensive part to change? Do you just change the sensor or do you have to change other stuff along with it? I may be able to get the guy doing my engine swap to do this too while he's doing it. IF it's not gonna add too much to the cost....... Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted July 12, 2003 Author Share Posted July 12, 2003 i think the cps on your engine wil be fine.If you want to change the cps to the 83 unit the right way you have to take the shaft out of the engine that runs the oil pump and put it in your engine.The shaft that runs the distributor in the 83 is splined and the one in the 81 is just round and smooth with a groove cut into it.I made mine work but it's not right, I will soon have a haltech so it won't matter i'll be pulling it out. Quote Link to comment Share on other sites More sharing options...
stagefumer11 Posted July 13, 2003 Share Posted July 13, 2003 i would also look at your EGR vavle, beleive it or not mine was faulty. and on a stock L20et. if flutterd on full boost. causing the lack of power. a cool sound , but.............well yeah you know what i mean. try it. take the line off it and block it. see what it does. Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted July 13, 2003 Author Share Posted July 13, 2003 i don't have my egr valve anymore but thanks for the info i'll take the one off of my ca18et i have in my lady's roadster.I have a 76 intake on my z now and it doesn't ahve egr on it at all. Quote Link to comment Share on other sites More sharing options...
fl327 Posted July 14, 2003 Share Posted July 14, 2003 anyways sorry off topic, found my problem. intercooler pipe blocking full movement of the distributor, couldnt clock it where i wanted to because pipe rests on it slightly, nudged it and found i had another inch of adjustment left in it!!!!! did the adjustment, and the stutter is gone, just went by the book on this one, checked spark before fuel, and it was all in the dizzy, YEAAAAAAAAAAH BOYEEEEEEEEEE Quote Link to comment Share on other sites More sharing options...
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