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What would cause this, i am working on this car for someone else, i know there are a handful of wiring that is not done the best way but overall it is running fine the first time it ran fine and got to 10 psi, the second test drive every time it got just past 0 psi on the gauge it would hit overboost cutout.
What would cause this, i have the purge and wastegate solenoid codes but looking into the 87 LM code that shouldn't cause this problem.
If you can get a scan tool hooked-up, do it! Then look at what it shows for manifold pressure, you might be having a repeat of the problem I had with my Omni when I first got it, which is to say a bad MAP sensor, telling the ECU that you're hitting 15+PSI when you're nowhere near that!
I actually had it cut out while still in vacuum.
The quick and dirty fix would be to try a KNOWN good unit from a different car, try that to see if it fixes the situation.
Mike
You're certain it's hitting overboost? It's setting a code for it?
If so, wrong map sensor? like maybe a tbi one?
Good ideas I know it is the correct Map I will try to log a run to see what the computer is seeing. Maybe the MAP is bad, Thanks
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I would check all vacuum lines and do a wiggle test on all the electronic connectors as well
Check for vacuum leak to the map sensor.
There's no OB set at 0psi. So, it's technically not overboost. But, if you have certain codes (TPS or MAP especially), the rev limiter can be set very low. The rev limiter and OB use the same shutdown code. So that it may seem like you are hitting OB, but it's actually a limp-mode rev limiter at like 3k rpm.
Check for MAP or TPS codes.
Great information thanks, I know it had a TPS code in the past, this could be it.Quote:
Originally Posted by ShelGame
This is actually in a sand rail like some may seen in another thread and the ecu is wired wrong so it clears codes everything you shut it off, I am going to rewire it correctly and go from there.
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Ok hopefully some of you can answer this in this thread instead of a new one, the wiring for the ASD is messed up, I have read that the relay for the ASD is inside of the power module, Does this mean that the ASD output directly powers the coil, injectors, and Fuel pump with no other fuses or relays?
That's correct. Once the ASD is triggered it's straight to everything on the Z1 circuit with nothing to stop it.
Great thanks for the infoQuote:
Originally Posted by cordes
my old van was doing that when i bought it. found out they had a non turbo map sensor wired in....
first test drive after fixing a bunch of wiring, still doesn't make sense ran good but popped pipe off when i let off with no bov any idea what can cause this
https://lh3.googleusercontent.com/8h...4=w440-h524-no
also really weird when i use a otc 4000 or MPScan the RPMs drop when it starts logging or communicating, also as i will upload in a log the cylinders are indicating weird retard on mp scan, i don't think i was seeing that on the scan tool,
Another thought could EMF be messing stuff up, the bulk of the wiring is right next to the coil, i know i couldn't get reading on other logging stuff anywhere near the coil
log file i tried to clip it to the driving time
https://drive.google.com/file/d/0B6S...ew?usp=sharing
Now I am getting these codes as soon as I turn on the key, I am getting sick of this thing, :mad: I tried different LMs same thing, must be something else in the wiring
Adding weirdness to the list MPScan gives the codes above but the otc 4000 only gives 12, 31, 36
found out that the MPScan is the problem with weird codes, made a few good passes and found that the TPS code like Rob suggested is causing the 3k RPM limiter and what i thought was overboost, i hope that changing that in addition to all the crappy wiring i already fixed will finish the job
Just to wrap up the thread, new TPS fixed the problem, and got it running good.