1986 Fresh rebuild no start

[fcdrifter13]

Posting this for a friend

 

specs

1986 fresh rebuild

all stock

removed the EGR

doulbe and triple checked the timing

and also changed the maf

 

the thing that is bugging us is that it has to be something stupid simple because the problem seems to keep changing.

 

The night that we put the motor in it started right up first crank but would not rev over 2k, i figured it was because we did not have the MAF piping all hooked up and we also adjusted the timing a bit with the same effect, so hooked all the piping up and still the same thing, so it lead us to believe that it was the MAF. We changed it out with a known good with the same result so we changed it back and now we have a no start situation with either MAF. Checked and replaced the wiring to the CHTS because we found that it was broken, still no start. No know that we are getting fuel and spark at the plugs, but it doesnt seem to be hitting but one or two times, then nothing for a few cranks then one or two times again. At this point and time my friend is highly pissed because his car will not run, which is understandable, but now I am starting to get pissed because for a week now all we can do is get it to spit a couple of times and have run out of ideas.

 

This is what all else we have tried

Unplugging the MAF to get it to start, nothing

Unplugging the ALT signal wire because we have heard of stories of no starts with a bad alt, should we try unplugging the actual wire on the back as well?

Resetting the ECU, nothing

starting fluid, it started occasionally but not everytime.

 

 

Right now the way the dizzy is set it actually slows the cranking down like it is hitting too soon and we have tried it in other positions with no avail just better cranking.

[jasper]

What color is the spark?? Are the plugs posssibly fouled?

Enough cold start enrichment? What is the fuel pressure?

[fcdrifter13]

What color is the spark?? Are the plugs posssibly fouled?

Enough cold start enrichment? What is the fuel pressure?

 

 

Blue/yellow spark, plugs dont seem to be fouled ill check again right now, fuel pressure is good.

 

THe cold start enrichment thing I have not heard of, where do I check this, I looked in the FSM and didnt see it but maybe I missed it somewhere.

[fcdrifter13]

Alright we couldn't get it started so we ran the self diagnostic and this is what it showed:

11- CAS

12- MAF

13- ChTS

23- TPS which we tried to unplug

31 - AC/ Load (driver side of manifold)

41 Fuel Temp Sensor

 

Now what we cant figure out is that the distributor was just replaced in July so why is it saying that the CAS is bad?

Ive also read that if it displays both CAS and MAF then the CAS is the cuplret so once again its throwing me off there too.

CHTS the wiring is bad.

 

WE are completely at a loss of what to do.

[fcdrifter13]

Ok we finally got the car to start but it will only rev to 2k, THe ECU is still flashing the same codes as above. Would a code 11 cause 12 and 13 aswell if the CAS was bad?

[specialk]

Ok we finally got the car to start but it will only rev to 2k, THe ECU is still flashing the same codes as above. Would a code 11 cause 12 and 13 aswell if the CAS was bad?

 

IIRC (check out z31.com to be sure) 2K rev limit is almost always MAF.

[fcdrifter13]

Ok we got it running perfect and for searching reasons Ill actually post the answer. We could here a hissing noising coming from one of the intakes so we took the upper off. Used a drivers license over the ports on the lower to confirm that we had a good seal. Started looking at the plenum gasket and found where the leak was, loaded it up with RTV and now it runs fine.