Hi there,
To anyone that can help. I recently "finished" doing the swap and have been tinkering with it to try to make it work smoothly. Currently, I'm trying to figure out why it won't start right up when I crank it. It won't start until I spray some quickstart into the plenum through one of the vacuum ports. Once it's on, it runs fine. I hooked up a fuel pressure gauge to the fuel rail to monitor the pressure to make sure it had adequate pressure during crank. Sure enough, it was at about 40 psi while cranking, then quickly dropped back to zero within a second after I finished cranking. Once it starts, pressure maintains at around 40 psi. Can this drop in pressure before it starts be the source of the problem of why it won't start right up when cold?

I tried crimping the fuel line coming from the fuel pump and the return line to see where the pressure release was coming from. That didn't work... maybe I did it wrong?

Or can it be the MISSING/PLUGGED 9th/coldstart injector valve that is causing the problem? I was under the impression the 89's didn't need it. When I got the tpi conversion, I was told it came off an 89 IROC, but the fuel rail had the valve port on the drivers side like the 85-88's so I plugged it. The runners don't have the open port on the drivers side, so I'm assuming they're from the 89. Basically, how do I know if the ECM is sending a signal to all 8 injectors rather than the BYPASSED 9th while cranking during cold start? Should the ECM be sending such a signal. I've read the 89 MAF system was the only year it didn't use the cold start valve. It still used the same 'puter as 85-88, right? (01227165)

Please someone help me figure this thing out... I want my van to start right up the first time everytime!!!!!!

 

You need to find out what prom you have, that will let you know if its thinking it has a cold start valve or not.

Your fuel pressure shouldnt drop like a rock once its primed. Its leaking out somewhere, whether backflow through the pump, or the FPR is dead. Doesnt sound like an injector leak.

 

yeah i thought immediantly somethin is goin on with the regulator, it shouldnt slam back to 0 pressure as soon as you kill the ign. if you find out why its doin that, you may fix your complaint

 

Thanks for the response!!! I rechecked the fuel lines again today with my brother... this time I cranked, he crimped the return line and the main fuel line coming from the pump and we found that the fuel pump isn't holding pressure. Sounds like the culprit...?
I'm using a universal MSD out of tank pump. Do you reccommend a different one?
Thanks.

 

Thanks for taking the time to read my post and reply...
I rechecked both fuel lines today and found that it IS losing pressure from backflow through the fuel pump. Would this be causing it not to start right up? What fuel pump would you recommend? I'm currently using an MSD universal out of tank pump.
----------
MADMAX...
What do you mean "prom"?

 

Chip, prom, its in the computer/ECM of the car. You need to know what is in there, if its for an 89 or something else. Doesnt really matter what runners, intake, sensors, or wiring. If you take the small cover off the ecm, there's a 4 letter code on the chip you will be able to see through one of the two holes in the blue plastic cover in there. Post it here, or look it up by searching and find out what year it is.

 

ive always had good luck with an oem pump, you didnt say what kind of car you had, but if its efi, then i know the oem pump would go in the tank, which would mean removing the tank for installation, i just like the intake pumps myself, let alone the cool fuel around the pump, helps for longivity, maybe upgrade with a aftermarket intake pump from holley or somethin, hope ive been helpful,