Cant pinpoint poor acceleration/ bad shifts

[tjh1127]

I just got my truck and im fairly new to these trucks when it comes to identifying common problems.
1995 c1500 RCSB 5.7 TBI 170,000 miles

Had the trans flushed and filled (didnt drop the pan) at the oil change shop along with synthetic oil. Had timing checked and advanced a touch from where ever it was(by mechanics recommendation).

Put in lucas stop slip and injector cleaner trying to determine a simple solution.

The problem is this. A. NO POWER, its so weak, my 93 blazer s10 has more torque and power than this thing by a lot. You floor it and barely move at all, and while its still warming up if you hit the gas it actually seems to bog down heavily.... B. Truck wont shift while accelerating, will rev all the way through the red zone and wont shift until i lift off of the gas. I got nothing.


I cant determine if the problem is in the trans or in the engine, seems more engine to me but, I'm a change my own brakes level mechanic so need some major help! lol

 

[someotherguy]

1 - 170,000 miles

2 - Had the trans flushed and filled (didnt drop the pan)

3 - Had timing checked and advanced a touch from where ever it was(by mechanics recommendation).

4 - Put in lucas stop slip

Go ahead and give it 5 - blast it with a few 12 gauge slugs through the radiator...

Do you know your fuel pressure?

Do you know where the timing is actually set?

Why would anybody flush to begin with, and even worse, not drop the pan FIRST to inspect the amount of debris in it AND CHANGE THE FILTER???

Why put a nearly worthless band-aid product in trying to fix an undiagnosed problem?

Sorry if I sound harsh but you may have taken a simple problem (fuel pressure, bad TPS) and made it many, many times worse.

Then again at 170K if your trans is original it's close to done anyway. Most 4L60E's are done by 150K or so.

Richard

 

[thunderstruck]

Throttle position sensor could be to blame for your shifting issue.

You need to have your fuel pressure checked. Needs to be at least 9psi, ideally 12psi or more.

Check the vacuum line from the throttle body to the MAP sensor, they tend to crack sometimes. The MAP sensor is underneath the air cleaner, near the firewall, above the passenger side valve cover. The line runs to the back of the throttle body.

The wiring connector for the coolant temp sensor can get corroded or otherwise damaged sometimes too. The sensor is on top of the intake near the thermostat housing. Check the ground wires on the housing stud while you're at it too.

One or both of those sensors could be bad themselves, but you really need to rule out fuel pressure before going there.

Also, is it sputtering, dying out, backfiring, etc. too?


Sent from my Nintendo 64

 

[thunderstruck]

Just a thought, if the mechanic who set the timing for you didn't know to disconnect the brown timing wire while setting it, your timing will be waaaaaay the hell off.

He may have also forgotten to reconnect it. It is underneath the glovebox, near the blower motor .


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[Mangonesailor]

...so need some major help! lol

Unnecessary "lol's"

 

[tjh1127]

Throttle position sensor could be to blame for your shifting issue.

You need to have your fuel pressure checked. Needs to be at least 9psi, ideally 12psi or more.

Check the vacuum line from the throttle body to the MAP sensor, they tend to crack sometimes. The MAP sensor is underneath the air cleaner, near the firewall, above the passenger side valve cover. The line runs to the back of the throttle body.

The wiring connector for the coolant temp sensor can get corroded or otherwise damaged sometimes too. The sensor is on top of the intake near the thermostat housing. Check the ground wires on the housing stud while you're at it too.

One or both of those sensors could be bad themselves, but you really need to rule out fuel pressure before going there.

Also, is it sputtering, dying out, backfiring, etc. too?


Sent from my Nintendo 64

Thanks for the detailed reply buddy. Trucks at the shop asked them to check all this.


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[michael hurd]

You could have plugged exhaust, or a myriad of issues. Check fuel pressure. Change fuel filter as well at the same time. Pull the spark plugs and do a compression test. If they are all fairly even, then you know you don't have issues there.

As mentioned the grounds are a good place to check as well, the one at the thermostat housing usually corrodes off. Check the battery to engine ground as well as frame to battery.

Have someone check the TPS with an analog volt ohm meter throughout its sweep.

Check for vaccum leaks and a bad EGR valve. Does it sound 'lopey' at idle?

 

[tjh1127]

Well looks like the first mechanic who did the inspection lied cuz there is no way he inspected this thing. Name something replaceable and it needs replacement. Entire front end including suspension, intake gasket leak distributor rusted all lines rusted and poorly patched power steering pump leak. $$ thousands in repairs to start. Either selling or digging and replacing with a 383


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[mpyusko]

Dirty injectors or bad spark plugs would be my first thought.

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