Driveability Help

Beigg

Beigg

Club Member
Looking for some driveability tech help here.
I have this 96 Blazer 4.3L that has a bogging issue when you press on the gas.

The fuel pressure is steady at 52 psi (hot and cold test) , the flow is there (checked volume=great) .

Swapped out MAF, TPS, and check for vacuum leaks and propane tested to make sure.

It starts right up and idles great, but when you give it gas in N it bogs down and will stall if you floor it. If you put it in drive or R it will idle, but will bog down/stall when you try to accelerate it any.

No codes are present, and I am thinking it's the distributor unit (it has the all in one unit) .

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Thanks.
 
I dont think it has a cat on it anymore, but i will check.

Thanks for the super fast replies!
 
The cat has been removed and the y pipe is not factory (slightly bigger than factory from what i see) .

Anymore thoughts?
 
you able to watch the fuel pressure when you drive it?


also, put a scan tool on it and look at cam retard, it needs to be 2 degrees, +/- 2 degrees, if it is off, you get weird stuff happening, only sets a code if it is off over 20 degrees, you set turning the dist., but you can't from the factory on the 4.3, so if it is off, you likely have an excessively worn dist. gear, not uncommon
 
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My scantool cannot see cam degrees. It only seeing ignition timing -20/-21 it will fluctuate accordingly to rpm's.
So would putting a new distributor shaft/gear in cure this problem?


You cannot drive this vehicle at all. It will not drive, under any load it will stall (going up a driveway, slight incline to road etc etc) .
 
dave89iroc said:
96 will be OBD 2, fairly basic compared to newer ones, but OBD 2 none the less
Click to expand...

Some of those were goofy like that. 95-98 was a gray area. OBD 1 was gone, but still lurking, and obd 2 didnt quite make sense of itself yet.


Best of luck you and your blazer my dear friend.
 
Buddy had the same problem and I believe it was distributor, i'll confirm for ya tommorrow when i talk to him
 
Thank you for helping me, I am waiting on parts right now to give this another go.

I'll post an update later on this evening or tomorrow morning depending when it rains.
 
I put in a new cap and rotor with no change in the problem. Still a pos.

Next up is replacing the whole unit. If that brings me no change, then I will assume it's the crank timing... By that I mean, it might have jumped a tooth or two.
 
Have you checked your induction system (tb and intake) for carbon build up??

maybe it needs an indction service? im sure you checked your air filter and such...
 
Yes the air filter is new, oil is not due for another 2K miles, I am at a loss right now. When you have it idling and goose it at the TB or inside cabin (makes no difference) it bogs down and will want to stall and if you hold it there or keep giving it more it will stall.
 
Put in a new distributor unit and it's still being a pos.

So the list goes as follows:
Cap
Rotor
Distributor Unit
TPS
MAF
No DTC's
Great Fuel pressure hot or cold engine on or off
No vacuum leaks
WTF????
 
dave89iroc said:
also, put a scan tool on it and look at cam retard, it needs to be 2 degrees, +/- 2 degrees, if it is off, you get weird stuff happening, only sets a code if it is off over 20 degrees, you set turning the dist., but you can't from the factory on the 4.3, so if it is off, you likely have an excessively worn dist. gear, not uncommon
Click to expand...

I might have to chalk it up as that being the issue.

:punchball
 
Well I took all the parts back and decided to drop the tank to bench test the flow rate of the fuel pump. Results were what I expected and I would have never found the problem IF I never dropped the tank.
I fed the pump a constant 12V's at about 15amps. It gave me 50+PSI, the more I increased amps and volts the pump didn't respond to it. I went and bought a new pump. Re-applied my testing to the new pump and the pump increased speed and volume as I ramped up the volts and amps.

Slapped in the new pump assembly and now the POS is blazin down the road once again.
This is the THIRD pump. Dealer did one, small shop did the second, and here I am doing this one. That is what the carfax shows atleast.

Thanks GM for yet another junk design.
 
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