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Bought this truck last February with a blown head gasket. It had been sitting for a couple of years. Got the head resurfaced put in new gaskets and put it back together. Fired right up but was blowing a ton of smoke. It had about an 8th of a tank of bad gas, but I've added another 10 gallons of premium. Have since put on new plugs, wires, cap and rotor, fuel filter, fuel pump, fuel injectors, air temperature sensor, and fuel pressure regulator. It would start right up and had a rough idle which would soon die. It would rev out and was smooth enough to risk driving it around the block. Got half way around before it died. After 30 minutes or so it would start back up. I pulled the ECU and saw a little corrosion and my kid who is a mechanic, tried some circuit board cleaner just to see what would happen. Then for the first time in 4 months it stopped firing. no spark at all. As there was some minor corrosion I got a remanufactured ECM and installed it. Still no spark. Truck is frustrating the hell out of me. Thought the ECU was the problem and now no spark. Spent over 4 months trying to figure out the Fuel injection and now I have to figure out the ignition system as well. Why would the spark suddenly stop after working for so long??
 

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For no spark: Did you check the voltage to the coil? If you are getting voltage to the coil, you may want to check the coil itself. If you sort that out and get it to start but still have a rough idle and then it dies, check the connector to Mass Airflow sensor. It makes a sharp bend at the connector, and the rubber that surrounds that connector can get brittle and crack over time and corrode the connection. Happened to me. Please let me know what you find as us B2600i owners have to stick together. Here is my 91. I am the original owner and still running fine at 207K miles.
10398
 

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What kind of money do you have into it Jeb?
That's a beautiful truck! I bought mine for $900 with a blown head gasket. Fixed the top end and then the fuel injection system got all messed up. I bought a reman ECU but haven't tried it yet as now there's no spark. A friend tried to clean the corrosion off the original ECU and it shorted out. I've replaced the fuse a couple of times. With the new ECU, I get no spark.

10399
 

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That's a beautiful truck! I bought mine for $900 with a blown head gasket. Fixed the top end and then the fuel injection system got all messed up. I bought a reman ECU but haven't tried it yet as now there's no spark. A friend tried to clean the corrosion off the original ECU and it shorted out. I've replaced the fuse a couple of times. With the new ECU, I get no spark.

View attachment 10399
That's a beautiful truck! I bought mine for $900 with a blown head gasket. Fixed the top end and then the fuel injection system got all messed up. I bought a reman ECU but haven't tried it yet as now there's no spark. A friend tried to clean the corrosion off the original ECU and it shorted out. I've replaced the fuse a couple of times. With the new ECU, I get no spark.

View attachment 10399
Nice truck man!
I forgot, I have about $2,500 into it
 

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Hi Jeb,
A few questions:
If you can narrow it down for me a bit, I can look in the shop manual and send you some further / better information if I know what circuit we are dealing with.

Also, keep in mind that just because someone re-maned the ECU, it doesn't mean that it's good. I have purchased many re-maned parts that turned out to be DOA and then had to find another before I got the issue resolved.

I want to see this little guy running.

Hang in there, these trucks are worth it.
Chris
 

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Hi Jeb,

Let me dive into my shop manual. I'll shoot you over anything that might get this solved.

I'll get back to you ASAP.
 

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Hi Jeb,

Now that you have spark but no EFI signal, it is sounding more and more like the ECU again, even though I know you replaced it.

I have attached shots of the troubleshooting section of my Mazda shop manual that deals with this issue. Please have a look at them and then we can discuss further if anything is not clear.

I have also included a link to a company I trust to rebuild them right (just in case). You can find them here: B2600i.com | Engine Control Modules G618-18-881, G630-18-881, ECM ECU

Have a look and let me know. I'll be happy when you tell me it's purring.

Hang in there,

Chris
 

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Discussion Starter #12
Hi Jeb,
A few questions:
If you can narrow it down for me a bit, I can look in the shop manual and send you some further / better information if I know what circuit we are dealing with.

Also, keep in mind that just because someone re-maned the ECU, it doesn't mean that it's good. I have purchased many re-maned parts that turned out to be DOA and then had to find another before I got the issue resolved.

I want to see this little guy running.

Hang in there, these trucks are worth it.
Chris
The old ECM was blowing one of it's fuses. Not so with new ECM. My son is a mechanic and gave it about an hour this weekend. It's getting spark and will run if carb cleaner is sprayed in the intake. He was trying to find what signal goes to the ECM that causes the injectors to pulse, He was looking for the crank sensor to see if that could be it but ran out of time. I really appreciate your support by the way.
 

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Discussion Starter #13
The old ECM was blowing one of it's fuses. Not so with new ECM. My son is a mechanic and gave it about an hour this weekend. It's getting spark and will run if carb cleaner is sprayed in the intake. He was trying to find what signal goes to the ECM that causes the injectors to pulse, He was looking for the crank sensor to see if that could be it but ran out of time. I really appreciate your support by the way.
Hi Jeb,

Now that you have spark but no EFI signal, it is sounding more and more like the ECU again, even though I know you replaced it.

I have attached shots of the troubleshooting section of my Mazda shop manual that deals with this issue. Please have a look at them and then we can discuss further if anything is not clear.

I have also included a link to a company I trust to rebuild them right (just in case). You can find them here: B2600i.com | Engine Control Modules G618-18-881, G630-18-881, ECM ECU

Have a look and let me know. I'll be happy when you tell me it's purring.

Hang in there,

Chris
I saw that site but tried both the phone number and email and got no response. Both my son and I were trying to figure out if it was new reman ECU.
 

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Discussion Starter #14
Hi Jeb,

Now that you have spark but no EFI signal, it is sounding more and more like the ECU again, even though I know you replaced it.

I have attached shots of the troubleshooting section of my Mazda shop manual that deals with this issue. Please have a look at them and then we can discuss further if anything is not clear.

I have also included a link to a company I trust to rebuild them right (just in case). You can find them here: B2600i.com | Engine Control Modules G618-18-881, G630-18-881, ECM ECU

Have a look and let me know. I'll be happy when you tell me it's purring.

Hang in there,

Chris
I'll check this out and do as much of it as I can. Thank you so much. By the way, it's really been six months not four that I've been working on it.
 

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Discussion Starter #15
I'll check this out and do as much of it as I can. Thank you so much. By the way, it's really been six months not four that I've been working on it.
I'll check this out and do as much of it as I can. Thank you so much. By the way, it's really been six months not four that I've been working on it.
I'm not sure how to check for codes. Do you hook up a test light between the single green terminal, which is next to the two terminal yellow terminal and the 6/3 green terminal by the windshield wiper motor and the fuel pump, to ground?
 

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Hi Jeb,
The terminal in question is simply grounded directly. No test light. Then the check engine light on the dash pulses out the code. This is OBD1, pretty lame I know, but this is how it works. I can go into the shop manual and find the section that discusses this in more detail, and then send those pages to you.
Kind regards,
Chris .
 

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Hi Jeb,

Please check out this YouTube video. It will give you a good rundown on getting codes from your truck

 

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Hi Jeb,
Look at this video at minute 9:10. It specifically describes how an igniter issue will cause a lack of pulse signal to the injectors.
 

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Discussion Starter #19
I tried that and nothing flashes. I do have 12 volts going to the injectors. On the circuit opening relay, the resistance is correct however when checking the voltage specs with the key in the ON position, the B and Fc show 12 volts. In the start position, the B shows 12 volts, the Fp shows 10 volts and the STA shows 8 volts. I obviously can't check the Fp at idle as it doesn't idle.
 
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