91 mr2 n/a engine problem - Toyota Nation Forum : Toyota Car and Truck Forums

Manafico · 02-16-2011, 12:18 PM

My 91 mr2 non turbo runs great but after driving it for about 15 miles it will stall and won't restart for 5 to 10 minutes. This is very frustrating because I work on a military base and the gate is right at 15 miles away and today it stalled right as I got to the gate causing a little bit of traffic to build up behind me. When it stalls the check engine light and a couple other warning lights come on. It will turn over but seems like the engine isn't getting any fuel. I have read the other threads where people report similar problem but nothing seems to be the same. I live in the desert where it is very dry and cold in the mornings. Once the engine stalls and is restarted the problem doesn't reoccur. It only happens once until the next day. It holds its RPMs just fine and doesn't seem to be anything related to where it idles. I ran a fuel cleaner through it and the previous owner changed the ECU and ran Sea Foam through it to try and fix the problem but didn't work. I am going to change the spark plugs today to see if that helps but I am stumped. My dad thinks it sounds like vapor lock but that usually happens when it is hot outside and the temp is around 30 degrees. If anyone has had a similar issue or knows what might be causing this I would really appreciate the advice.

***MR2Jedi*** · 02-16-2011, 01:01 PM

Test your fuel pump.

Manafico · 02-16-2011, 04:21 PM

Thanks. I am going to change the fuel filter so when it stalls again I can check for fuel going to the engine and make sure it is the fuel pump. I went to the mini mart on base at lunch and when I got back in my car it wouldn't start again. It didn't start for about 15 minutes this time. I have a feeling it is either the filter or the pump. Hopefully its not the pump because I will have to drop the tank to change it. Do you know how long it takes to change?

Jason.MZW20 · 02-17-2011, 09:54 AM

Quote:

Originally Posted by Manafico

Thanks. I am going to change the fuel filter so when it stalls again I can check for fuel going to the engine and make sure it is the fuel pump. I went to the mini mart on base at lunch and when I got back in my car it wouldn't start again. It didn't start for about 15 minutes this time. I have a feeling it is either the filter or the pump. Hopefully its not the pump because I will have to drop the tank to change it. Do you know how long it takes to change?

Quite a few hours, maybe even the better part of a day/night if it's your first time. I've dropped my tank twice now.

You have to remove the entire e-brake assembly and just unbolt the A/C and coolant pipes. You also have to remove the shifter cables, and fuel tank heat shields. It's still not easy, and it'd help to have a lift, though it's doable on jack stands. You may have issues getting the main filler hose off because the rubber tends to bond quite well. There are two EVAP hoses you need to disconnect as well. The fuel pump and sender connectors are underneath the center panel where the ashtray sits, so some dash disassembly is also needed.

It's just time consuming. While the tank is out, it'd be a good idea to replace the filler gasket and of course the fuel pump housing gasket. The fuel pump sender you can't get a gasket for unless you buy the whole assembly, so don't worry about that.

What you could do is test the fuel pressure before the filter and test it after. That'll tell you if it's the pump or the filter. Or you can change the filter and cross your fingers.

Russell D · 02-17-2011, 11:19 PM

I would be fairly certain your problem is your fuel filter. A few years ago by brother had a eagle talon that did the same thing; everything would be great then the car would get starved of fuel and die, then it would not re-start until it sat for about 10minutes. I changed the fuel filter it didn't do it for about a week then started again; someone must have put sugar or sand or something in the gas tank.

Manafico · 02-21-2011, 07:05 PM

So everything I have changed so far include the fuel filter, spark plugs, air filter, cap and rotor, and have ran fuel system cleaner through the system. It still continues to stall and not start for 5 to 15 minutes. I am trying the things that I can afford right now before I dive into the expensive time consuming parts. It is either the fuel pump or the ignition I think and I want to be sure which one it is before I spend the money for those parts.

Jason.MZW20 · 02-22-2011, 11:54 AM

Check the fuel pressure w/ the return line clamped or directly from the fuel pump line which I believe is a -6AN line.

For the engine to stall, the pressure would have to be pretty low as the engine uses whatever fuel is in the rail. The ECU controls the fuel pump relay ground (circuit opening relay labelled C/OPN). If you want to prime the pump manually with the IGN ON, use a paper clip and short FP and +B under the diagnostic cap. If the engine restarts faster than before, you may have found the issue, but I'd still check the pressure.

Manafico · 03-02-2011, 08:33 PM

So the last time it didn't start I checked the spark plug wires and wasn't getting any spark. When it started I checked again and spark was there. So now I am pretty sure it isn't the fuel pump and most likely is the ignition. Anybody ever had similar issues? I am thinking its the distributor but would like to be sure before spending $150+ on the part. Any advice is appreciated.

MR-Deuce · 03-11-2011, 10:58 AM

i have a 91 n/a and i had a crack in the coil housing and even the slightest bit of moisture would shut the car down. mabee with the dramatic temp changes its building moisture. try looking over the coil pack.