'88 350 TPI, on cold start runs OMFG rich. Stumbles. Bogs, dies. Once it hits closed loop, runs great and no real issues.

About a month ago it through code 43 MAF, so we swapped in a new one. It was throwing the CEL and surging occasionally at cruise. The cold start problem got progressively worse even after the new sensor. The car has always been a bit nasty about starting but never super rich and blowing smoke like this.

Things we've checked:

MAF, new plugs and wires, new fuel filter, fuel pressure, fuel pump, distributor, cold temperature sensor, grounds are all clean, plugs are clean, MAF burn relay...

Wtf are we missing here? The plugs were fouled out. New plugs and wires, much stronger spark and fires off quicker but still running rich as **** (until closed loop, when magically, everything starts working great).

'88 w/cold start injector delete. LT4 hotcam, ZZ4 bottom end, Vortec heads, EGR delete. 30# Ford SVO injectors. 180* thermostat.

Any and all help would be fantastic. About the only thing untouched at this point is the computer...

 

https://www.thirdgen.org/forums/post...856-post2.html

 

Its amazing what a constant will do

 

My thoughts exactly.
30/22 = 40% extra fuel

 

?

Sorry about the double post. I posted this from my phone earlier on my lunch break at work... I also wasn't quite sure which forum to post in. And then I realized TPI was probably the best one

To clarify this post as well, car has been running the same tune for about the past six years... I sent a series of dyno pulls to Fast Chip and they burned the current tune. EGR delete, 9-th injector delete, etc. It's been working splendidly for a very long time.

Just noticed the post about relays in the TPI forum as well... the relays have been swapped out, but I'm starting to think they aren't the right ones. Some of the posts in that thread describe my troubles fairly closely...

 

The current tune is based around the 30# injectors.

 

Your first post said you haven't done anything to the ecm and I fact Ed has compensated for the injector size off the constant and maf tables. If this is a new occurrence removing the ninth injector if its still on your fuel rail to see if its leaking or if it has been removed watch the cts reading during cold start it maybe defective.

 

Sorry, I'll clarify a bit more.

When I meant it hadn't been touched--I meant thinking about replacing it (about five years ago the car got a new ECM but kept the same PROM). The car has been together and running for seven or eight years now with no major issues. 9th injector is still in the rail, its just disconnected. CTS was replaced with a brand new part, but since its only ten bucks I'm willing to throw another one at it.

About a month ago it threw the MAF code, and we replaced it--along with the relays. I just noticed the thread in the TPI forum about using the correct relays causing REALLY ODD issues and I'm going to investigate tomorrow and make sure the correct relays are being used. The super rich start WASN'T an issue before this; it's always been a little reluctant to start until its warmed up, but this is definitely new. Warrantied out the first MAF as well, same behavior.