No Start - Noob Needs Help

[onslow]

Needed to install new crank sensor and IAC because car was stalling. The fuel pump & filter, ICM, coil pack, and plug wires are new too.

After install, the car fired right up. I chose one of the several IAC/TPS reset procedures out there and this is what I got at closed idle:

BLM 131
IAC 16
TPS 44
MAF 6
RPM 800
WOT 4.54

On the road, the car ran great with no stalls, but with just a slight stumble at 25...but it would continue on throttle with no other problems.

Last weekend, just for the halibut, I decided to get more experience tuning the car by trying a different IAC/TPS reset procedure to see if I could 1) match the good scan numbers I got last week and, as a separate thing, 2) track down a fix for the stumble.

So, I started the car and it idled great. Then I shut it off, and did one of the other reset procedures (clip into ALDL, unplug, plug in IAC, etc.).

Unfortunately, I did not have the engine in CLOSED loop before I began. I went at the reset procedure with an OPEN loop state. When I tried a restart, it ran several seconds then died.

So, I tried doing every other reset procedure out there (including the TPS and min. air screw adjustments). The best I could get was for it to run for a minute with me cycling the throttle, but it would die without my help...very frustrating.

Now, I'm puzzled. Since the car ran okay after the new parts were installed, what did that second reset do to the car that will not let it run?

How can I get it to run so I can tune it???

My only idea is to unplug the ECM, then check IAC pintle position, reinstall the IAC, unplug the crank sensor and crank the engine...then replug the ECM and try firing it again. That is how the car was set up when it ran after I first replaced the IAC and CPS.

Any other ideas out there?

Thanks for your help!

Steve

 

[ponykiller]

the 1st time the car is started the iac is learning, when the car is turned off it stores the info into the computer and uses the new no.s as base line when you start the car, the computer sets the rpm's it uses th iac to controll it so the iac needs to be about 20-30 ish the lower the no (5-0)the less controll the car has to keep the idle at about 800 rpm, take a reading when the car is really warmed up... ck your plugs and wires too a mini tune up

also tps is on the high side make it about .40-.42
give me those readings again when the car is warmed up

 

[onslow]

Ponykiller-

Thanks...all good advice! The plugs are clean and the wires new, throttle body all nice and clean.

The problem is that the car will not start and run...so it is impossible to get it warmed up to reset anything.

Any ideas on how to get it started now that I have screwed up all my good work?

Steve

 

[ponykiller]

un hook the maf sensor and see if it runs (power cable to it is just fine) , if it runs its the sensor, go to this site and read every thing but i want you to read BASICS twice
http://www.vortexbuicks-etc.com/

 

[onslow]

Ponykiller-

Thanks. Found vortexbuicks long ago - great resource and rely on his expertise. I will try MAF unplug. Working on car today and will let you know what happens.

How long have you had your turbo beast?

Steve

 

[ponykiller]

it's going on 17 years... my wife has been driving it for the last 6 years, have not done any thing for the last 5 years too, just recently last 3 months i have been working on it when she gets home...
she allways tells me how she races covettes, irocs, stangs and even porshes.
at 1st she did not like to drive the car because it was to fast for her, then people would ask her about the car and she would watch me race and learned from it and now she loves it... i tell her it was made to be drivin hard so do so, and she does

 

[onslow]

Ponykiller-

First off, I want to thank you for what is apparently the fix for the car...the MAF.

When I disconnected it...voila, the car started. Nicely enough, another member has kindly offered to send me a working MAF so I can be sure.

I think I got a little fooled trying to diagnose the problem because I got a code 34 on rare occasions before, but after clearing the ECM, the code did not come back and the car would start. However, the code is back full time now. Perhaps the MAF was on its way out with an intermittent problem.

Funny, in all I have read here and there about no starts, the MAF was never mentioned...it is always the CPS, IAC, ICM, CS, etc. Now I am going to dig thru MAF posts to see if I missed posts saying that a bad MAF can result in a no start.

So, again, MANY thanks for your advice...I really appreciate the education...especially the fact that you knew about vortex! As they say..."you are the man." And, since your wife likes the occasional street shootout, she must be a great person too.

I will keep you posted on my progress.

Steve

 

[ponykiller]

we are all one big family here, you might want to update that old style maf sensor to a LS1
2 places sell them http://www.fullthrottlespeed.com/index.asp
and
http://turbotweak.com/payment2.htm
you will need the translator, LS1 maf sensor, Adapter hose, 3.0" to 3.5" to go to your inlet pipe, if you dont have the pipe fullthottle has one and lastly
K & N Cone Air Filter
3.5"

the old maf sensors are hard to come by and the remans don't work all that well.. check out them 2 sites

btw.. take that 180 thermo and put in a 160 and look into a turbo tweak chip, eric is a great guy and your car will run like a bat out of hell

 

[onslow]

Ponykiller-

Nothing like family!

I appreciate the information.

Borg Warner and Niehaus sell new MAFs at local parts stores. What do you know about how well they function?

Will a 160 thermo allow the car to pass smog in California?

I have already been in touch with Eric about chips and have a 4x9 K&N for the "big mouth" setup (air from behind air dam).

Steve
onslow@myway.com


P.S. Is a bat out of hell as fast as a long-tailed cat in a room full of rocking chairs?

 

[ponykiller]

call or e-mall eric and he will make a chip that will make the car pass smog
go to the turbo tweak site and you will see he also sells the translator and the ls1 mass air flow sensor