Ignition BS? (fixed)

[TYRODD]

Okay, today I was tinkering around and started triple checking my vac system. I found no leaks BUT I broke a nipple of of a check valve so I had to go get parts. I decided to replace all the lines anyway, just to do it. In the process of replacing the FPR/MAP/Upper int. man. harness I noticed a strange ruddy oilish fluid leak out. I had the whole thing out and blew on on end, which caused a large amount of the substance to shoot out all over my engine comp. as well as myself :x . After replacing that harness, I started her up-problem "solved"!!!!!!!

I believe this was the problem and my hypothesis on it is that the fluid was blocking off the needed vaccum to the fpr and would cut off fuel intermittently.

Holy shit I feel like a jackass! :banghead:

It still sputters a tiny bit though, I think its just residual fluid left over. I cant believe I have spent over $350 dollars on ignition parts, only to find that it was a dirty vaccum hose :banghead: . I guess I still have a fresh ignition system, ready for spring though .

Also, I finaly capped of the vaccum ball hose, is it normal for it (heater/AC)to hiss under high boost?

I HOPE this fixed it, thanks everyone for the input anyways, and hopefully this may have helped others!

RJ

 

[gmcturbo]

i get a hiss like youre sayin too. you prolly hear it now becase youre actually getting vac!! good job

 

[Lynn D. Brown]

problem disappears when I drive the truck hard, as the heat produced might allow even a crappy o2 sensor to work.

Not sure the O2 has any function or control at all @ WOT. Don't think so.

 

[TYRODD]

Well, the 02 sensor had nothing to do with it anyways, but I did need to replace it as it had severe coolant deposits.

I guess dirty hoes/hose are never good! :lol:

 

[TYRODD]

Well shit the problem is back, and its worse. I may have made the problem less "noticable" by fixing the vac. line. The truck barely runs, realy sputters bad at 1/4 throttle from a dead stop, never dies though. I came out of an intersection the other day and the truck fell FLAT on its face, I mean, glad I had the seatbelt on. The tach does not seem to flutter anymore, just moves along with the engine vibration.

With key on engine off, fuel psi is @42-good. With engine started and vac line still attached to reg, psi @37-38, with vac line plugged, psi@ 47 (base psi). The guage needle moves VERY erratically when I open the throttle, definitly not a smooth increase of pressure.

I am also experiencing rich exhaust at idle, its bad enough to burn my sinuses pretty good. Then again, I can kill the engine, wait a couple minutes and restart it with much less fumes/hesitation.

When I replaced the plug wires, I did them one at a time to make sure I did not cross'em, pretty sure they are not the problem otherwise.

Pretty embarrasing when coming from a stop.

 

[Mario65]

maybe I missed it. Did you change the ignition module under rotor?

It was my problem though not as bad of a problem as yours.

 

[skata]

how old is the fuel filter?
does the fuel pressure drop when you give it throttle?
recheck all your electrical connections.

 

[TYRODD]

I replaced the Ign. module about 3500 ago, these things go bad pretty randomly though, however I dont think this is the problem as Ign. modules are either good or bad, not in between.

Fuel filter was changed last week, pump was replaced 3500 ago. Yes, the fuel pressure does drop "slightly" when I blip the throttle. All connections have been checked and coated with dielectric.

 

[Mario65]

I had a problem only after I got to operating temps.

 

[TYRODD]

Oh, also my fuel mileage is absolute shit, 9mpg on a stock truck w/K&N that is supposed to help, I used to get 12 and even then I though that was shit. This is not from driving'er hard either, I havent been able to in weeks(withdrawels are KILLING ME).

 

[SY2455]

Hi, I would recommend that you use the service manual to test your ECM as some the stuff you had going on, went on with my truck after I repaired & cleared my trouble codes. I found out by testing it, that the ECM had failed in two areas.

1. Fuel - the Fuel pressure gauge was jumping around.

2. Spark - the computer was sending out a fake knock signal

The chip was not affected, it was the computer itself.

The truck is now up and running, if you would like more information about steps I took, then read the posts under "Chipping, Emissions & Tuning" called "Code 43 will *NOT go away, no matter what I do."

my replacement cost on the ECM was $78.99 (exchange)

 

[TYRODD]

Hmmmm, I am not pulling codes at all, could still be a bad ECM but dont want to think about that! I am going to take it to a GM master tech tommorrow, Ive given in. :x

 

[TYRODD]

Okay, the Typhoon is still in the shop, Randy (tech) believes that the problem lies in the MAP and or the ECM. He CANNOT communicate with the ECM, he is using a "Genesis" scan comp. He also noticed the EGR was leaking a little, I told him justblockthesombitchoffitdontneedtobeonthereanyways! , and he agreed.
He thought the map/fpr vac. harness was also not hooked up right, however I know it is as I have have studied numerous diagrams, I am bringing him a copy of one tomorrow for verification/ He also said there are NO vac leaks.

With the EGR blockoff plate in mind, Randy just has a piece of sheet steel blocking it off-not too pretty. Ive seen someone on the board with an aluminum plate with "GMC" etched into it,...got any more? Me likes!

 

[TYRODD]

Problem solved!!!! MAP was bad, as well as a fouled plug. Compression, timing, vac lines, FPR, and all other Ign. components checked out okay.

Randy's scan tool he used before was for newer cars and thats why he couldnt scan the computer, he used his older one and had good results.

The truck runs like new, and I am anticipating much better fuel economy!

Thanks again for all the input!!!!!!!!