got no acceration

[emo666]

ok--my 1989 ranger 2.9 not accelerating . It starts fine runs fine at low speeds---but push done and it bogs and goes nowhere. It has no engine light or codes. Changed out ignition module on distributor,changed coil, new MAP senser. Map senser fixed it for a week or so but now its back to where it was. Great for around town at 30 mph but don't try to pass anyone as it acts like the old buick dynoflow trannys (Dated myself). If it was exhaust would it run good for aweek or so?

 

[Dirtman]

What's your fuel pressure and when's the last time it got a fresh fuel filter?

 

[Bird76Mojo]

Another 2.9 finds another victim. lol

What Dirtman said.. Check the cheap stuff first.

Search here or Google for how to check the throttle position sensor voltage. Make sure it "sweeps" smoothly.
Check fuel pressure at the fuel rail.
Don't bet on that new ignition module being any good. Many of them are junk even though they're new.
Buy some MAF spray cleaner and clean your mass air flow sensor. Do NOT touch it or blow it dry, etc. It's very delicate.

We recently had a member here with similar issues, and he had no codes either. It ended up being his O2 sensor.

One thing that can't hurt is to visually check the throttle body butterfly to see how far it's opening when someone floors the accelerator pedal. Do this with the engine OFF. If it doesn't open all the way, then you can use a few zip ties on the throttle cable where it hooks to the pedal. This just removes any slack so you get wide open throttle via the pedal.. Do it one zip tie at a time so you don't over-tension it. This won't cause your issues, but checking/fixing it won't hurt anything and will help restore lost "power"

Many times when checking other components, you'll run across something else that may be causing your issues. It never hurts to get to know your truck a little better..

 

[rusty ol ranger]

Test the fuel pressure like dirtman says.

Sounds like its definatly fuel related.

 

[PetroleumJunkie412]

Guessing fuel as well.

Bosch O2 sensors work well. Rock Auto carries the correct one.

What brand was the MAP sensor you picked up?

 

[PetroleumJunkie412]

Another 2.9 finds another victim. lol

??

 

[Dirtman]

Guessing fuel as well.

Bosch O2 sensors work well. Rock Auto carries the correct one.

What brand was the MAP sensor you picked up?

Bosch makes the o2 sensors for motorcraft.

When I see posts like this where a bunch of stuff was replaced. It makes me cringe. The new parts dont help diagnose the problem, they add more questions.

AFTERMARKET ELECTRONICS ARE TRASH.

so I try to diagnose based on the original problem and ignore what was replaced. For example a coil could be the problem, you replace the coil and the problem persists. That means dick if you bought a parts store coil with a 75% failure rate.

 

[emo666]

fuel pressure good--but have a partial fuel symptom maybe?..been having for years tho didn't seem to bother the truck. I can't fill the gas tank more than 5 gallons at regular nozzle speed than I have to drizzle fuel into gas tank or it will back out an splash out of the fill pipe. Had a garage supposedly fix it but never was right. Just throwing that out--maybe someone has had that to. (P.S.--usually do my own work but did not want to mess with draining gas tank).
don't know make of maf sensor -bought at O-reilly's - coil bought at federated parts store. Will buy oxygen sensor at rock auto and check catalytic unit for back pressure--may just bypass it

 

[rusty ol ranger]

fuel pressure good--but have a partial fuel symptom maybe?..been having for years tho didn't seem to bother the truck. I can't fill the gas tank more than 5 gallons at regular nozzle speed than I have to drizzle fuel into gas tank or it will back out an splash out of the fill pipe. Had a garage supposedly fix it but never was right. Just throwing that out--maybe someone has had that to. (P.S.--usually do my own work but did not want to mess with draining gas tank).
don't know make of maf sensor -bought at O-reilly's - coil bought at federated parts store. Will buy oxygen sensor at rock auto and check catalytic unit for back pressure--may just bypass it

Sounds like you may have a blocked EVAP line.

When your puttin fuel in the air thats being displaced has to go somewhere, usually through the EVAP system. If that air isnt escaping its building pressure as you pump fuel untill the pressure becomes so great it cannot be overcome by the gas pump.

Then it spits it right back out the only place it can, the filler neck.

When the fuel pump is pushing fuel to the engine air needs to come in, otherwise a vaccuum is created and the engine no longer gets fuel.

Try leaving your gas cap off and filler door open and take it for a drive and see if your symptoms improve.

 

[Dirtman]

Like rusty said filling like that is because of a block, more specifically it's a clogged evap canister vent line, the canister itself is clogged, or there is a small output hose that sometimes has a filter on it and that can get clogged.

When your filling the tank air needs to escape because it's being replaced by fuel. BUT the opposite happens when driving, that vent needs to let air in since fuel is leaving the tank.

Do what rusty said, drive with no gas cap for a short distance.

 

[emo666]

Very little improvement with gas cap off--going to new oxygen sensor and check exhaust-ran some seafoam thru also- no go!!

 

[Dirtman]

I love seafoam, but never seen it truly "fix" an existing issue, it's more for preventive maintence to keep a good engine running well. Id still check the filter, a clogged filter can provide enough pressure but not enough volume.