1990 Mazda Bravo engine electrical

Tiny
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  • 1990 MAZDA BRAVO
  • 2.6L
  • 4 CYL
  • 4WD
  • MANUAL
  • 200,000 MILES
Howdy, I would like to pick up on a post by Jaxxxon of about 3 years ago, listed near the bottom of the second page of this make and model. I rebuilt this PU about a year ago and it ran strong until it developed this problem. It starts and runs fine until it starts to warm up, then dies. I can hear the relay behind the glove box clicking, engine starts to cut out, then dies and wont start until it goes cold again. I have tried all kinds of tests, checking spark, fuel pressure, timing, compression, valve timing have concluded that the problem is electrical. Found a running pu at junk yard and bought all the electronics, changed one part at a time, distributor, coil, igniter, computer, with no change. Then purchased new temp censers, (coolant and air), wires, plugs, fuel pump, fuel regulator and dampener and fuel relay. Still it starts good when cold and runs for about 5/10 mins then dies and will not start until it is once again cold, I can unhook mass air flow and makes no difference when running or starting. I work on cars a lot but this has me stumped!
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Sunday, September 27th, 2015 AT 5:14 PM

12 Replies

Tiny
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I have had other makes doing this, and found it to be a faulty crank angle sensor, what is not working when it stops, no spark, no fuel pressure on injector pulse?
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Monday, September 28th, 2015 AT 1:31 AM
Tiny
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Howdy, thanks for your quick response. This is weird, I put a noid light on injectors and they are firing, In fact it will start and run on three cylinders, When I plug the injector back in, it quits. It does the same with coolant censer, unplug it and it will start, plug it in and it quits. It has spark when it won't start and good fuel pressure 40 lbs. This earlier version of Mazada does not have a crank position censer. It appears it picks up timing from the distributor. I have replaced the distributor using one from a running pu. I have 2 of these and lots of extra parts. Timing has not moved, I thought I might have something off on distributor gearing, but all is together, there is a pin on the camshaft that aligns the dist gear and it can shear, but this one is fine. I changed the computer with no change. I currently have this pu away from my shop, I plan to haul it back home next week. I'm stumped but it has to be something simple.
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Monday, September 28th, 2015 AT 7:10 PM
Tiny
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On more thing, I have been away from the truck for a couple weeks, it had been running but not very good. When I first started it (after being gone) it started but would run idle up to about 2500 then drop back to 800 then accelerate up to 2500 then drop. It would take a couple seconds to make this cycle, did this about a doz times then died.
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Monday, September 28th, 2015 AT 7:19 PM
Tiny
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Check idle control system and check for vacuum leaks, any codes in the system?
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Tuesday, September 29th, 2015 AT 3:06 AM
Tiny
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Thanks for your response, I'm away from vehicle (150 miles). I have it at a project site where I volunteer, Plan to bring it back to my shop next week. Threre is no port to read codes (1990) But the manual talks about reading from a wire connection, I have looked for that but have not been able to find it. Color is not as described. Will search that some more once I have it back here.
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Wednesday, September 30th, 2015 AT 1:09 PM
Tiny
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Did you look at the post I referred to, sounds like the same problem.
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Wednesday, September 30th, 2015 AT 1:11 PM
Tiny
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Can you post a link to the post that you are talking about, I only see 4 questions for Mazda Bravo.
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Friday, October 2nd, 2015 AT 3:08 AM
Tiny
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Good morning, sorry, We've been away at a rodeo over the weekend. This vehicle is not a mazada bravo, It is a 1990 Mazada pickup B2600i. I will try to send you a link if I can figger out how to.
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Monday, October 5th, 2015 AT 8:18 AM
Tiny
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Look in Mazada, b2600, 2nd page 5th from bottom, 1989 b2600 runs 15 mins, then dies.
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Monday, October 5th, 2015 AT 8:23 AM
Tiny
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I would be trying a known good ECU, I have seen this with other models when the circuit warms up the circuit board distorts and breaks the circuit.
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Tuesday, October 6th, 2015 AT 3:52 AM
Tiny
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Good evening, We just got back to where the vehicle is, I brought a new battery.12.6 volts, It started right up but started cycling. Up to 2500 rpm, down to 1200, back up to 25, down to 12. I let it run for 5 mins. Just kept it up, has no throttle, soon as I step on gas, it falls flat. Checked running voltage and is 14.5. I shut it off after cycling for 5 mins. Running very rich black smoke.I'm gona clean the mass air flow, just cause. I pulled both the air and coolant temp censors while it was cycling with no change. I have another CPU at my shop, when I get the truck hauled back home next week I will change it out.
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Tuesday, October 6th, 2015 AT 4:53 PM
Tiny
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Check the fuel line pressure if the fuel pressure regulator is faulty, rail pressure will be too high and the exhaust will be black and sooty.
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Wednesday, October 7th, 2015 AT 2:09 AM

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