I'm about at my wits' end with this one...

I pulled my truck (1992 S-Jimmy, 1990 L05/700R4) in the garage the other night to see if I could straighten out the rough idle. Turns out the one injector was leaking/pissing a little bit, so I pulled the injectors and the lower seal on the one was a little beat so I threw a new one in. The pattern is a lot better, both are giving a real nicely atomized mist just like they should be (while cranking anyways). Only problem is, now it won't start. It sounds like it wants to, it stumbles like clockwork while cranking, it just won't fire up.

I made sure I didn't bump or move anything, nothing is disturbed or disconnected, there's plenty of fuel in the tank, etc etc...

Is there something I'm not thinking of or...?

 

an engine needs four things to run:
fuel, air, spark, and compression.

find out what you're missing.

 

yeah thanx tons- I hadn't thought of that

anyone actually helpful?

 

alright, awesome. you can figure this one out yourself if you're going to get an attitude.

 

heh... i love bickering

If you move the dizzy around does it start it? Basically what I'm asking is, is the timing right?

So you have pretty much determined that you're getting fuel.

Check the quality of spark. Test all the items on the distributor to make sure they arent crapping out on you, and see where you are from there.

You have compression, since the starter is spinning it.
You have fuel since you have seen the spray pattern (I'm assuming)
You have air unless you're blocking it off somewhere (doubtful)
Sounds like the quality of spark is the only thing NOT checked over

 

yeah i think at this point the quality of the spark is the only thing I'm not sure about, I put a spark tester on it and while cranking none of the cyls are getting a 100% spark every time, it's like 1 strong pulse then 3 or 4 weak ones, then a good strong one again. I don't know if that's a normal ESC/EST function or ?

I hate to admit but I started throwing parts at it although it's not really too big of a deal since I have 2 or 3 of pretty much everything. So far I've swapped the coil, est module, distributor module, map, iac and ecm just for the hell of it. All this was after checking the map, tps, cts, etc etc...

The distributor doesn't turn at all so the base timing should still be correct(?)...

I was able to borrow a friend's fuel pressure gauge tonite so I'll have to check that tomorrow just to verify. I'm almost kinda hoping it is the fuel pump, my fuel gauge has been acting up for a few months now so that would give me an excuse to drop the tank & fix both at the same time

 

The distributor cap has a spring loaded button that makes contact with the center of the rotor, did you check it? part of it may have broken off.

 

of course this isn't a third gen, but it can be third gen related which is probably why the thread is still open.

i take it that you pulled the injectors out of the TBI without removing the TBI from the motor.
you had a fuel leak which you repaired, during the time you had the injectors out you probably had fuel dripping into the intake.
it was running rich because of the leaking seal, add to it the extra fuel getting into the motor during the repair, to me it sounds like you may have some fouled plugs.
i would pull the spark plugs, if they are black, replace them.

 

good call Denn. I didnt even think about that .

KISS

Yeah, throw some new (correctly gapped) spark plugs at it and see where that leads yah.

 

I thought about replacing the plugs too- I forgot to mention one of the 1st things I did was to pull all the plugs, clean them up and make sure they were gapped right. I also left them out overnight that night so hopefully the cyls would dry out. I would hate to have to replace them cause they're less than 1 yr old, same as the coil/wires/cap/rotor/wires/etc etc

I meant to take a look at the contact button inside the cap when I had it off but I forgot and put it all back together

I'm heading out there now to get working on it

does anybody know if the erratic spark strength I mentioned is normal? Can't say as I ever checked a good running engine just for the hell of it...

 

the spark should be the same all of the time, a low or weak battery can have an effect on it as can bad grounds & power problems.
on a good GM ignition system with the external ignition coil, with the high tension wire off at the coil the spark should be able to jump down the side of the coil to the laminations on the coil when cranking almost everytime it fires.

 

Here's something helpful...this board is for third gen F-bodies only. If I want to read about trucks, mom's old Buick, etc. I can get that pretty much everywhere else but here.

 

He is being helpful.

Token's reply is approriate, and in no way sarcastic, or condesending.
Sometimes we have to step back to the basics. The answer is in one of those four requirements, or their quality.
If you think he's was only telling you what you already know, then obviously you don't, or you would have posted, not only the problem, but the answer as well, so that others can learn, and benefit from the experience, which is one of the reasons for this forum, and I don't think there's any dedicated member here that doesn't give as well as get.