Sluggish engine, need help

[tybee]

I just bought a 1991 camry. It has the 4 cylinder, 5 speed. 70,000 miles.
When I drive, if I really step on the gas it drives ok just not that much power, but as I let off the gas and the pedal is almost all the way up theres a spot that the power kicks in. I took it in at a local fix it shop and they told me they thought it was a gumed up fuel system and the timing was 45 deg. instead of 10 deg. Well they cleaned the fuel system up and adjusted the timing and it acts a little better but hardly any power. I cant drive from a stop with the A/C on. Thanks

[Toysrme]

The timing belt slipped... They were stupid to clock the distributor in an attempt to fix it.

Replace the timing belt. Might as well replace the waterpump and ahve them flush the coolant while they're at it.

Don't go back to those mechanics, they're idiots.

[tybee]

I can see that being the reason for the timing. But what about the acceleration issue. Thanks

[techspecs]

There could be a few things to check.

Without knowing what the "experts" at that shop looked at, and assuming that the ignition components checked out ok (plugs, wires, and distributor cap etc.) and hopefully they checked the fuel pump was operating properly with the right pressure I would suggest the following:

If the engine sounds fine at idle and while accelerating (power issues aside) and doesn't miss or backfire I wouldn't worry about timing. (any backfiring and I'd take it back to that shop complaining)

I'd first check the air filter to make sure it wasnt clogged. I've seen rare cases that the filter was fine but there was debris in the hose before the filter so the passageway was clogged but it was not easily found. The best way to check would be to disconnect the intake hose at the throttle body and run the engine and rev it up to see if there's a big difference DO NOT DRIVE IT WHILE DISCONNECTED. If there is a noticable difference and the filter looks clean try using compressed air to blow out any debris. Also I would inspect the throttle body to see if the plate is gummed up which would affect acceleration.

[tybee]

Thanks, I checked all that. Could it be the throttle position sensor?

[techspecs]

Is there a check engine light on? If so you can take it to a local auto parts store for a free check. If the throttle sensor was faulty it would most likely set a code.

[Toysrme]

No it wouldn't be the TPS sensor. The TPS sensor is only used to trigger open-loop mode, and adjust the transmission shifting patterns.


... Cam timing has a huge correlation on performance.




Guys, please try to troubleshoot in a logical pattern instead of random things that have no bearing on the possible problem.




The car runs horribly. The ignition timing was found to be at 45*. There was no maintinance done before, that would have advanced it 35*.

1) The two 12mm brass/aluminum stretch bolts that hold the dstributor on and set the timing are NOT going to back themselves out by themselves.

2) The engine outputs rotate in a counter-clockwise fashion. If the distributor WAS loose, the timing would have been retarded from that motion, not advanced.


There-hence-forth, the timing can not be advanced, without some one advancing it. It should be obvious, that the ignition timing is not the problem.


The only other way the ignition timing can advance is if the valvetrain itself is advanced (The distributor is driven off the end of a camshaft). That can happen during valvetrain/timing belt installation, or the timing belt can slip on the valvetrain cogs. Since no maintenace was done. We are left with the timing belt having slipped.



That is how you troubleshoot in a logical manner. techspecs no offince, because we're all trying to help, but everything you've mentioned either has no bearing on the problem, or is incorrect.






Valve timing will run on one tooth slipped, most people never know the differance. By 3 teeth, most engines will run like complete crap.






FYI - The timing belt has slipped three, or four teeth.



At the very least replace the timing belt.

[tybee]

Thankyou, but thats not what I wanted to hear. LOL