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1998 Mazda b2500 Repair Question


Topics covered: Fuel pressure, Spark, Compression.
Mileage: 175,000 miles.

Asked on December 23, 2011

Does not start

Has fire has injector pulse has air has fuel has fuel pressure timing is on has compression does not start no codes no security fault
Avatar Asked by Kevin Godwin

Answer

Replied on December 23, 2011

http://www.2carpros.com/articles/car-cranks-but-wont-start

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine atleast 3/16 away from ground-have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, Do you hear the fuel pump come On when you turn key on? If not check fuel pump fuse and fuel pump relay if okay-check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs,coil's resistances,cap and rotor,distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it and keep testing

Tiny Answered by rasmataz
68 questions asked
Replied on December 23, 2011

done all the above (basics) still nothing even tried a used computer like stated in post above has fire has injector pulse has fuel pressure and timing is dead on. no codes or security faults

Tiny Response from Kevin Godwin
11 questions asked
Replied on December 23, 2011

How did you check the timing that is dead on-also what is the fuel pressure?

Tiny Answered by rasmataz
68 questions asked

Replied on December 23, 2011

pulled the timing cover off and checked cam and crank marks
fuel pressure 35psi
injector pule and pulse width looks great as well

Tiny Response from Kevin Godwin
11 questions asked
Replied on December 23, 2011

Are you so sure its on the compression stroke instead of being in the exhaust stroke-180 deg off-

Tiny Answered by rasmataz
68 questions asked
Replied on December 23, 2011

yes and truck has cranked and ran perfect once since problem did not recrank rechecked everything though still found nothing wrong all numbers look good all sensors read good all waveforms are good

Tiny Response from Kevin Godwin
11 questions asked

Replied on December 23, 2011

You got compression, fuel and spark it should be able to combust I can't think of anyting else

Tiny Answered by rasmataz
68 questions asked
Replied on December 23, 2011

thats what i thought too but

Tiny Response from Kevin Godwin
11 questions asked
Replied on December 23, 2011

Something is still amiss between the 3 elements

Tiny Answered by rasmataz
68 questions asked
Replied on December 23, 2011

i agree but i can hook a compression gauge and fuel pressure gauge a noid light and a spark tester all at the same time and everything is there even tried and egr valve thinking maybe its stuck open letting to much (used) air into combustion chamber to run......

Tiny Response from Kevin Godwin
11 questions asked