Bogging down. Backfire. Running rich? Heavy fuel smell.

[shift321]

Hello! Need some help. I'm having an issue. I have a 1992 MX-3 with a 1994 626 engine in it. I bog down like crazy anytime I hit the throttle under 2000-3000 rpms. There is also a backfire if I'm quick and heavy on the pedal. If i go easy into the throttle it takes off nice and smooth with no bog down. When I open my windows I have an intense gas/exhaust smell also. But only with windows open. When they are closed I smell nothing. Smells like I'm running rich.

[kulluminati777]

maybe a bad distributor? Maybe an HEI and external coil would help. The bogging down the unburnt fuel....screams no spark or inadequate spark.


Someone should make a cut and paste thread answer. This seems to be the most common and largest problems lately. The distributor.

[shift321]

I have replaced cap, rotor, and sparks. Made no difference.

[kulluminati777]

oh ok well I was talking about replacing the actual distributor. Or doing the HEI and external coil set up. Im sure your problem is 99.9999% the disty. Although im not physically there so i wouldnt know for sure.


The "running rich" you speak of seems to be unburnt fuel in the cylinders from getting little to no spark. I had the same bogging issue under 3000-4000rpms then above that it would be a sputter or bog here and there but nothing like under 4k. I had checked everything. My fuel pump, the relay, plugs, wires, the cap, the MAF....everything that had to do with the spark, air, and fuel. Replaced the distributor and the issue was solved. Until the disty died out again. I then tried the inexpensive and reversable HEI and external coil mod and that was 3 years ago with no issues.....

[Daninski]

Ok the guy above me answers disty for every post he replys to,,, Could be a disty issue but first go over your entire top end and check for vac leaks. Make sure all the hoses and caps are installed and not cracked. If your still using the stock rubber intake then it could be cracked. If so fix with GOOP. Does the car act up when cold as well as warm?

[kulluminati777]

Ok the guy above me answers disty for every post he replys to,,, Could be a disty issue but first go over your entire top end and check for vac leaks. Make sure all the hoses and caps are installed and not cracked. If your still using the stock rubber intake then it could be cracked. If so fix with GOOP. Does the car act up when cold as well as warm?

my last few posts have been disty related lol. I only thought ignition related because of the above 3k bogging thing. I didnt even think of a vac or intake leak.

[SuperK]

it could be your:
VAF (air flow meter) is sticking shut
heavy vacuum leaks (intake tubing mostly)
injector stuck/o-ring damaged
distributor (the distributor has an internal coil that could be defective, common issue. changing plugs/wires/cap/rotor is different than the actual coil)
O2 sensors

Have you checked for codes? I would pull the codes and see if there's anything obvious.

[atx_mx3]

Have you checked for codes? I would pull the codes and see if there's anything obvious.

This is where I'd start.

[RX8SE3P]

yes check codes first. my bet is coolant temp sensor for the ecu.