88 Vert, no engine mods except for removing TB/BAC from water path. All three cats are punched out.



Symptoms:

It will turn over, rev up then die. If I pump the throttle, I can force it for a few seconds.

It's turning slow (below idle), and I get very little throttle response.



First diagnosis:

Acting just like my truck did when I had a massive intake leak (maeaning, a 4 inch cut in the intake tube).

The pressure sensor is not hooked up (snapped the bung off of the UIM, going to fix that today)

There was a green connector betwen the block and UIM that is not connected. It's a big one, with the wire lock like the BAC connector or injectors. I could not for the life of me find where it went, and I didn't disco it when I pulled the UIM. However, it's missing the wire lock, so it's possible I just pulled it apart. I'm had the UIM off before, and don't remember it them? https://www.nopistons.com/forums/pub...1047683561.gif



My feeling is that it is not an intake leak (seems to be fine). I don't think the lack of the pressure sensor will prevent it from running. I'm going to scour my FSM now, but I thought one of you UIM experts would recognize the green connector...



Thanks all!

After reading some threads, it's the "boost sensor" on the wheelwell that is disconnected.

After putting a new starter in (it's a bitch trying to diagonose problems when it only starts after banging on the starter https://www.nopistons.com/forums/pub...>/rolleyes.gif ), I can get it started consistanty, but must give it throttle to keep it alive. It'll rev to 4K (probably more, but don't want to blow something right now). But, it does seem to be missing power (won't rev as quickly as it should) and it will still die when I stop giving it throttle.

Start looking for vacuum leaks. Get someone to hold the car at about 1k rpm, and start spraying starting fluid or carb cleaner or water around the vacuum lines and intake gasket surfaces. If the rpm chances then youve found your leak.

Gotta go buy starter fluid...

Now it will idle at 1500rpm just fine (in fact, it's a better idle than I'm had in a long time https://www.nopistons.com/forums/pub...). But, when I give it throttle, it'll surge up a few hundered RPM, then drop back down, even if the thottle is still in. Can't get it above about 2100 no matter what I try.

I can hear a vacuum leak, just gotta find it...and I still haven't gotten the boost sensor installed.



Oh, and I pulled the 6port sleeves out, that wouldn't change things like my idle speed, would it?



Is there a way to pull codes from this thing?



I'll keep beating at it (hell, it's only 100 degrees outside), but I'm hoping someone else has come across these symptoms.

OK, my car is possessed.

Went to get the starting fluid. Came home, started it up...

And it idles and revs fine https://www.nopistons.com/forums/pub...>/rolleyes.gif

Idle is too high, the thermowax isn't cutting out soon enough, but other than that, it's fine.



I hate diagnosing EFI crap https://www.nopistons.com/forums/pub...1047683358.gif https://www.nopistons.com/forums/pub...1047683358.gif

yep, MAF based EFI sucks. 99% of the time, problems are vacuum leak related.



if you want to eliminate that headache, get a standalone that is speed/density.