Tentatively solved my rich, hot start, fuel issue.
Thread Starter
Senior Member
Joined: Jun 2002
Posts: 415
Likes: 0
From: Cincinnati
Tentatively solved my rich, hot start, fuel issue.
For those of you that don't know my car had the following symptoms:
Ran rough when I first start it cold (like on one rotor), acted flooded when it was hot and stalled if I didn't give it gas for about 30 seconds, plus it ran rich and idled high.
The biggest part of the problem turned out to be that the fuel pump relay was not getting voltage from the ECU to activate when the ignition was first turned on. After scratching my head for a few months about what could be causing an interruption between the ignition switch, ecu and fuel pump relay - it clicked. It was my freakin turbo timer. I unplugged the damned thing, and sure enough - voltage at the fuel pump relay for 2 seconds when I turn on the ignition. Starts and idles fine, and doesn't run rich.
I spent roughly a year searching the forums, and testing/replacing parts. I went as far as to take it to a Mazda dealer and give them a shot at it. After it was all said and done I spent roughly $1,000 , took the UIM off 3 times, pulled the injectors and had them rebuilt, replaced the FPR, replaced the fuel pump, replaced the coolant temp sensor, replaced the plugs and wires, tested just about every sensor, did a few compression tests, and replaced most of my vacuum hoses since I was already pull the rats nest apart. So, needless to say I'm happy that the problem is solved - but at the same time pissed off that I didn't think of the stupid turbo timer sooner. For the record, the timer was installed already when I bought the car 4 years ago - and up until last spring there had been no problems. If I had just installed the timer and the problems started, that would have been the obvious place to start.
-Charlie
Ran rough when I first start it cold (like on one rotor), acted flooded when it was hot and stalled if I didn't give it gas for about 30 seconds, plus it ran rich and idled high.
The biggest part of the problem turned out to be that the fuel pump relay was not getting voltage from the ECU to activate when the ignition was first turned on. After scratching my head for a few months about what could be causing an interruption between the ignition switch, ecu and fuel pump relay - it clicked. It was my freakin turbo timer. I unplugged the damned thing, and sure enough - voltage at the fuel pump relay for 2 seconds when I turn on the ignition. Starts and idles fine, and doesn't run rich.
I spent roughly a year searching the forums, and testing/replacing parts. I went as far as to take it to a Mazda dealer and give them a shot at it. After it was all said and done I spent roughly $1,000 , took the UIM off 3 times, pulled the injectors and had them rebuilt, replaced the FPR, replaced the fuel pump, replaced the coolant temp sensor, replaced the plugs and wires, tested just about every sensor, did a few compression tests, and replaced most of my vacuum hoses since I was already pull the rats nest apart. So, needless to say I'm happy that the problem is solved - but at the same time pissed off that I didn't think of the stupid turbo timer sooner. For the record, the timer was installed already when I bought the car 4 years ago - and up until last spring there had been no problems. If I had just installed the timer and the problems started, that would have been the obvious place to start.
-Charlie
Thread Starter
Senior Member
Joined: Jun 2002
Posts: 415
Likes: 0
From: Cincinnati
It was a Greddy model - at least 4-5 years old. I didn't install it so I'm not 100% sure if they used a harness - from what I saw under the dash, it looks like they did though.
-Charlie
-Charlie
Thread Starter
Senior Member
Joined: Jun 2002
Posts: 415
Likes: 0
From: Cincinnati
Just an update - the problem came back. Now it happens even with the paperclip in place of the fuel pump relay.
I am convinced that the problem is heat related - since it is happening now that the weather is warm after going through all the cold months without problems. I guess its back to searching and testing...
-Charlie
I am convinced that the problem is heat related - since it is happening now that the weather is warm after going through all the cold months without problems. I guess its back to searching and testing...
-Charlie
Thread
Thread Starter
Forum
Replies
Last Post
alphawolff
1st Generation Specific (1979-1985)
17
Nov 17, 2015 05:57 PM