It started after the truck setting for a week over thanksgiving. I was off school, and only worked the Monday and Tuesday of Thanksgiving week, other than that, she sat until the following Monday night.

It starts hard - cranks about three,four,five times before it fire. It idles fine after that, but stalls easy if you max the steering wheel all the way to one side - like backing out of the drive, and the wheel hits the stops. The PS pump seems to really strain the engine. Shifting from part to reverse tends to stall the engine too - I have to gas it up a bit to keep it from stalling.

While driving, the engine chugs real bad under power - or a lack of power I should say. Any torque it used to have, is nearly gone. It's driveable, but acts like fuel disappears while accelerating. About 15-30 miles an hour can be a little hairy trying to come off of a stop.

My question is: If I were to intentionally cut my rusty return line, and vacuum evaporator canister line (There's three steel lines coming from the fuel sender) , and main "pressure" line, would it make dropping the tank any easier? I would repair the lines with fuel injector hose, some sand paper to clean the rusty spots off the line, and hose clamps. I'd cut the old tank straps (They're 23 years old after all), and replace them, the sender and pump - possibly the filler neck.

I have come to this conclusion from all my testing I did today: TLDR Question: Is there any foreseeable problems with my intentionally cutting the fuel return and evap line (My "pressure" line has already been replaced and attached to my rusty sender with injector hose) to drop my fuel tank and replace my fuel sender/pump assembly?

 

Have you checked the fuel filter or tested fuel pressure? I would definitely do that before cutting lines and straps.

 

I replaced the filter beginning of summer, but I have not checked the pressure yet. I think if my pump lasts long enough, I'll check it while I'm at school. They have a kit there that has the right adapter for my truck. I got one of the actron adapters for $8, but I can't find a pressure gauge that'll work with its awkward sized test port.

 

Well, as it turns out, my boss, who is a very experienced driveability technician, helped me looked at my truck, and he came to the conclusion that my issue is my ignition system. So ... the only part I didn't check. My distributor cap and rotor were corroded, and he is also suspecting my distributor is worn out. I replaced the cap and rotor and my issues seemed to go away. It still stumbles under WOT or heavy acceleration, but I can at least drive it.

Fuel pressure was a solid 9 PSI and vacuum was really strong at 20. I had another guy, who's hairs are much greyer than my own (He's an oldschool carburetor guy) look at it, and he was really astounded by my strong vacuum. Apparently, the engine's in really great shape. I just need to figure out if my distributor is garbage or not.

The dizzy was replaced back in '96 when we had the engine swapped with a rebuilt one. The technicians who swapped the engine had issues with it starting, so they put in a new distributor. I don't know if it was remanned, new, OEM, aftermarket, a dizzy they pulled from another engine - but either way, seems like it's having issues now.

Alldata and mitchel ondemand5 both say spec is 9-13PSI acceptable fuel pressure. We were able to break torque and check PSI, we idled with PSI, and we let it set there. After key off, the pressure drops immediately.

Thus far my check list looks like:
Swapped injectors
Fuel pressure is 9 PSI
20PSI of vacuum (Actually, I don't remember if it was in HG or PSI ...)
Replaced fuel filter
New sparkplugs
New cap and rotor
New ICM
New Spark coil (A little MSD blaster coil I had setting around)
Base timing is just off 0 degrees (Spec is 0 degrees, but I'm fine with where it is)
The spark plugs are clean, and I'm not burning any foreign substances

Short of a compression check, which I think is unnecessary at this point, what I have done so far seems to cover my bases.

Does anybody have any other ideas for me to look at?

Who knows anything about adjustable fuel pressure regulators for these TBI units? Worth getting one and moving up to 13PSI? I've read that these GM TBI units like around 13PSI. Mine's on the lower end of the scale. Would 4 PSI make a big difference?

 

If it s still stumbling pull the dist. shaft out and look at the gear.

 

Well I fixed the problem.

What I think was going on, was that the spark plug ends by the plugs weren't actually contacting the plugs themselves. The issue is that the terminals that are inside the plug boots were slid out a little, and the boots were just shoved over the plugs. I don't think the plug terminals were properly clipped over the plug ends.

I bought a new set of plug wires, and I put in a new distributor, reset ignition timing, and she runs like new! My old distributor's points that house the pickup coil were bent. So the teeth that are supposed to create the magnetic spikes for the pickup coil, weren't lining up properly, giving the truck an erratic spark condition. The other issue with the distributor, was on the gear, it looks like the rebuilders mashed the end of one of the teeth that are by the roll pin. Looks like they missed when they were pounding the roll pin out.

I'll post up some pictures tomorrow. It's too dark and cold to go outside again

Thanks you guys for your help!

 

Here's the gear on my distributor:


Here's the cage that houses the pickup coil on top of the distributor:


I don't think either of these issues will cause such an extreme power loss and misfire like I had, but I explains the somewhat lopey idle it used to have. It runs smoother than ever now.

 

First off the issue with the engine stalling but starting up hard, sounds like a low compression issue. Other than than i'm stuck, maby needs a small timing tweak, PS shouldnt cause it to lower more than a 100 rpm's.

I'd throw some seaform in there and get out all Carbon Build Up if you had that much gunk on all your other parts, you bound to have some **** on your valvs, and piston rings, could be causing low backpressure, and issues getting all amount of fuel and air through valves.

 

Thanks for the suggestion! I'll have to call up my buddy and see if I can't seafoam my truck there ... my neighbors, not to mention the fire department across the street, wont like all the smoke seafoaming creates.

Also, for the record, since this particular engine was put in the truck back in '96 by Michigan Motor Exchange, we have had faithful 3k oil changes. I honestly don't think there's a huge amount of sludge in the crankcase. It really wouldn't surprise me if the intake valves were gummed up though.

I happen to have a can of seafoam too ... I'll let you guys know how it goes. Could be as late as Friday though.

 

An update:

I need to change the information about my engine. Turns out, as per the info my dad told me, the engine was put in the truck in about 2006/2005. I think I got the '96 thing from my Fiero's engine ... which was also from Michigan Motor Exchange

Anyways, as my problem seems to develop further, I drove my truck today and it "seemed" to be better off than last time. Maybe because it's slightly warmer outside? I might just throw a coolant temp sensor at it and see if that helps. I did check the sensor with my snap-on multimeter, and I got 28k ohms from it on a 28°F outside, which seemed to match up with the chart I was using from ChiltonPro. So ... I dunno.

I drove the truck today and it ran okay. About two days ago, had to get some gas. Now, in the past, I usually go where it's cheapest; be it "Metro" gas (A new independant station near here), or "Independoil" Which is also "no-name" gas. But this time, I put in Shell. On the ride home after getting the gas, there was no difference. But today, after it sat for a day, the truck ran pretty decent. Still chokes a bit if you goose the throttle ... but was perfectly driveable. Perhaps I got some bad gas?

I think I'll check my ground cables to the block and frame ... maybe add a ground. Does anybody have any ideas? The only few things I have not checked are compression, and I haven't popped the throttle body off to look at the IAC airway and what not.

Strong Vacuum, swapped injectors, 9PSI fuel pressure, clean/new sparkplugs, new plug wires, new cap and rotor, swapped OEM distributor, properly set spark timing, new(ish) spark coil (MSD blaster2), OEM pickup coil and ignition control module that came on the swapped distributor, new fuel filter (as of early summer).