O.k., someone please help me diagnose my problem. I've been trying to figure out what's been going on with my car(1990 IROC 350 L98), and with minimal help from other people locally, I have been stumped as to what my problem is.. :

Symptoms:
The car idles very rough though maintains 1000Rpms. Sounds as if it had a really nasty cam(its all stock). When in gear, the motor's RPMs get really low and nearly stalls. A lightly white vapor comes out of the tail pipes with a lot of condensation which smells like gasoline(not a strong smell). Inside the cab, the gasoline smell is intense, and under the hood, the smell of gasoline when the snorkel is removed is also intense.

Tests:
Took a test light, grounded to chassis, tapped all distributor cap ends to see if all wires were firing. Saw that #8 wasn't firing or at least did not short out or cause RPM stutter during test. Tested different Plug wires to see if there was a bad wire, no other wires worked. Tested plug to see if it was a faulted plug, got a brand new AC plug, gapped, still did not fire. Noticed an amount of oil on the old plug and on new plug aswell when I pulled it again. Not sure if there is actually oil in the chamber, don't know how to tell. I took the valve cover off to check springs and rockers to make sure they were compressing correctly, and also to see for a crack in the head. Everything ok. Reassembled valve cover. Further tests on distributor, brand new cap and rotor. But now # 6 also is not firing(understand that the distr cap and rotor were new before any problems occured).

I've been told that I could have a bent intake valve and its slapping the piston, I could have a cracked block/head. I am leaking oil, but from the tranny meets the motor.

Im a novice to a lot of this stuff, but I'm trying to learn.

Help please.

 

Another thing, some wires from the wiring harness that go underneath the motor have disintiegrated or fryed. One that goes to the starter has melted at the tip, one that goes to the top of the oil filter reacts oddly when connected(when inserted into its plug, the fuel pump engages and will not shutoff, and this is with the cars key out of the ignition). Another lead off the battery into is completely frayed and detatched. I wish I had a dig camera to show what I mean.

 

anyone?

 

am I going to have to rebuild.. overhaul?

 

first thing to do is to make sure the prob is with the engine and not the ignition sys, it sounds like you have a major timing issue....pull the fuel pump fuse, take an old spark plug and attach the #8 (and later with the #6)wire to it insted of the engine' spark plug, and put the plug aganst the block and crank it (you may need a buddy for this....bewere you may get zapped if you hold the plug wrong)....you should see a spark.... next find out what those wires go to...the one by the oil filter sounds like the emergancy shut off for the pump...the oil pressure goes low and the pump stops to shut off the engine, that could be the prob., next check your fuel pressure low fuel pressure will cause your simptoms too, as the furl will seep insted of suqirting into the cylender, and the fuel needs to be atomized to burn properly, see the hats manual for checking the pressure, I have an aftermarket EFI setup and I'm not quite sure how to check it on yours...there will PROBABLY be a pressure port on the fuel rail that you need to hook a gauge up to, but to be sure get a hays or chilton manual....also remember to put back the fuse for the pump after the spark T/S up top...keep us updated, I have to go to work now, but I'll be back later.

 

Ok, when you say to test the old spark plug, do you mean, to have it out of the chamber to view whether its actually sparking across the gap?, which show that its not a bad wire/plug. I dont want to mess something up here, just making sure I understood you correctly.

I was told that the plug near the Oil Pump is possibly a fuel pump roll-over cut-off, and between that one and the one by the tank, there us a conflict which may be causing the pump to stay engaged.

I am thinking of replacing the whole harness, just not sure where to get one.

 

Ill try checking the fuel pressure, and Ive been told to do compression checks on the cyclinders as well.

 

by checking for spark with an old plug your seeing if #8 and # 6 spark plugs are getting a spark, you could have a bad cap/rotor (I've had one bad right from the factory, the brass inserts fell off while the engine was running....all of a sudden the engine started running real rough). also can you confirm that both pumps are running when the engine is on, that could be the problem too

 

I had the same thing with two separate problems adding to each other.

My vapor line to the tank broke and I believe my EGR valve is crap. I was running extremely rich and would stall if my car came down from high revs. You could smell gas inside too.

I found out about my EGR by forgetting to hook up the vacuum hose to the throttle body when I was messing around with stuff. Car runs great with it off and crappy with it on. I'm just waiting for it to get warmer out to replace it.

Remember the KISS principal! Have you rechecked the plug wire routing? Six and eight could easily go to the wrong location on the cap.

After you recheck the routing, and if you don’t have anyone to help you out, just start the car and pull the wires off of the cap and check for spark. If you can get a spark to jump from the cap to the wire, you could start looking else where. Injectors’ maybe?

Good luck, I know the headache you’re going through.

Scott

 

Did you take the pushrods out and make sure they are all straight as an arrow?

 

You know, 6 & 8 are among the most commonly mixed-up plug wires on a small block Chevy. Both short wires at the back of the engine running right next to eachother. Did you do a simple check of the plug wire routing to confirm proper firing order? 18436572

 

I got rained out today, so I couldn't do any work on my car, but one other thing:

When my car is running, amounts of gasoline start to seep from my tank. It appears like there are a couple of swells on the very bottom, and not like its dripping down from the top, as if the return was leaking, but almost like there is too much pressure in the tank and its coming out the bottom. But there are no visible holes, but what looks like to weld marks, not sure if they actually are, again... I wish I had a dig camera. This only happens when the car is running.