Floor it at idle and engine bogs down and dies - Toyota Nation Forum : Toyota Car and Truck Forums

94celica94 · 02-27-2005, 09:56 AM

At idle if I floor it quickly the engine will bog down and stumble and die. If you gradually give it gas, it will rev up just fine. This only starts happening after the car has been driven for 30-40 minutes. While accelerating from a stop the car just doesn't want to go, it hesitate badly. Also when you're cruising above 45 mph, the car will buck and hesitate occasionaly.

I have replaced the fuel filter and replaced the Throttle position sensor. I have run a bottle of fuel injector cleaner through the tank and put about 1000 miles on this car. This changed nothing.

I pulled codes and got a 31, which is Manifold absolute pressure sensor signal. I've heard that if the MAP is bad the car won't run at all. There is no check engine light present.

This car has 130K miles and just had another motor put in from a totalled vehicle. So I can rule out the engine, because this same problem was happening with the old engine.

I am thinking fuel pump. I have no gauge to check pressure though. Any other ideas? Would the code 31 have anything to do with it?

94celica94 · 02-27-2005, 09:58 AM

Forgot to mention, this is a '94 celica with 1.8L 7A-FE engine. 5-spd.

fredk · 02-27-2005, 10:46 AM

did you put a map sensor on it yet?

94celica94 · 02-27-2005, 02:22 PM

Quote:

Originally Posted by fredk

did you put a map sensor on it yet?

I have not swapped in another MAP yet. The Toyota parts counter and Autozone both told me that this car does not have one. But it is clearly bolted to the firewall.

fredk · 02-27-2005, 02:26 PM

ok, look at the vacuum hose routing diagram on the underside of the hood, look for it there

Super-D-38 · 02-28-2005, 04:00 AM

I'm really reaching here, but as with my problem, have you checked your fuel pump pressure?

Maybe the fuel pump is in the early stages of dieing..

94celica94 · 02-28-2005, 09:25 AM

Quote:

Originally Posted by Super-D-38

.... have you checked your fuel pump pressure?

Maybe the fuel pump is in the early stages of dieing..

I have not checked fuel psi. I don't have a gauge. How much are they and what type do I need? What's a good place to get one?

3SGTE CELICA · 02-28-2005, 04:21 PM

try changing your plug wires.
I had a similar problem before and it turned out to be the plug wires.
hpe this helps

Super-D-38 · 02-28-2005, 06:57 PM

Quote:

Originally Posted by 94celica94

I have not checked fuel psi. I don't have a gauge. How much are they and what type do I need? What's a good place to get one?

I'm not sure, I have a couple because my dad was a mechanic..

The way I tested was with a "compression" tester.. My psi was supposed to be 33 -38 and the compression gauge started at 20. so I figured it would work..

It didn't show any movement, so I tried a "weaker" gauge that only went to 10 psi..
the pressure showed what I would guess to be 15psi...

just about any pressure gauge should work, so long as it has the range you will need..
IE; 0 - 50 psi should be fine to test fuel and many other things..
I don't know what your car calls for.. but that sounds right.
(It may take some thinking and enginering to attach one to your car, as not every car has the same size holes and such)

Almost any parts store should have something..
My guess would be about $30 or less..

And like I said I'm just guessing..
Though a pressure gauge is nice to have when you need one.

94celica94 · 09-20-2005, 07:29 PM

It turned out to be a bad Crankshaft Position Sensor ( CPS ). I just replaced the whole distributor from another wrecked car and problem solved.

Dr Tweak · 09-21-2005, 12:23 AM

How did you figure out that it was the CPS?

94celica94 · 09-21-2005, 12:41 AM

Quote:

Originally Posted by Dr Tweak

How did you figure out that it was the CPS?

Well it was suggested by a mechanic I use for major work. He found a good deal on a used dizzy and said he was %80 sure that would fix it. I said go ahead and slap it on there and it worked.

94celica94 · 09-21-2005, 12:44 AM

Havn't been fighting this for 7 months either. Got it replace back in March, just now stumbled across my old post and wanted to post a resolution to help people in the future.

Search terms:
Crank Crankshaft position sensor distributor hesitate buck stall rev die plug wire wires fuel pressure

LaserDad · 05-23-2008, 11:48 AM

I fought a similar problem on my '90 Celica 5S-FE, for almost 2 years. It would occasionally start to buck, until you let off the throttle and slowly brought the RPM back up. It felt like a clogged fuel filter, but I replaced fuel and electrical components without any improvement.

It turned out to be a bad Engine Control Unit. Luckily I found one at a junkyard.