6 liter tuneup/bad miss & hesitation
10-27-2017, 07:58 AM
#1
95 F150 4x4 4.9L
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6 liter tuneup/bad miss & hesitation
I am new to the forum. I recently purchased a 95 F150 4x4 5 speed with the 300 inline 6. I knew the truck would need a tuneup when purchased, so I did some research and found a lot of others doing a 6 liter tuneup. Original driving manners were sluggish and slow for acceleration. Check engine light was on, and would have a miss when cruising in 4th gear
I purchased some Taylor Thunderbolt 8.2 wires, a Taylor distributor cap and rotor, ACCEL 140012 coil, and Motorcraft SP435 plugs to do my tuneup.
Original parts did not look too bad while replacing with new. Installed all new parts, and discovered rotor was broken, so had to use the one from the old cap. Got the truck running, and started to adjust the timing. I set the spark plug gap to .55, and we were shooting for 14 degrees of timing. I do not believe the truck has the original motor, because the timing marks were pretty off on the balancer.
Test drive went poorly, truck was bucking and missing in all gears, and especially under load. Made several more adjustments, and could not iron out the misses. It appears the wiring harness that runs to the distributor and coil have been tampered with as well. Where should I start on tracing back the issue? I’m going to start with checking all plug gaps again and move them back to .50, and maybe replace coil with original and see if that helps.
I purchased some Taylor Thunderbolt 8.2 wires, a Taylor distributor cap and rotor, ACCEL 140012 coil, and Motorcraft SP435 plugs to do my tuneup.
Original parts did not look too bad while replacing with new. Installed all new parts, and discovered rotor was broken, so had to use the one from the old cap. Got the truck running, and started to adjust the timing. I set the spark plug gap to .55, and we were shooting for 14 degrees of timing. I do not believe the truck has the original motor, because the timing marks were pretty off on the balancer.
Test drive went poorly, truck was bucking and missing in all gears, and especially under load. Made several more adjustments, and could not iron out the misses. It appears the wiring harness that runs to the distributor and coil have been tampered with as well. Where should I start on tracing back the issue? I’m going to start with checking all plug gaps again and move them back to .50, and maybe replace coil with original and see if that helps.
10-29-2017, 06:25 PM
#2
Senior Member
which timing marks are you going by? you cant use the ones cast on the timing cover.
theres a pointer and marks on the crank pulley, this is viewed on the passenger side.
it bears repeating that especially on a new-to-you 6, check fuel pressure.
my 96 doesnt like the timing advanced past 11, or there is some pinging. it does run better at 12-13 but 89 must be used. there doesnt seem to be any benefit advancing timing any further or higher octane regardless of timing.
theres a pointer and marks on the crank pulley, this is viewed on the passenger side.
it bears repeating that especially on a new-to-you 6, check fuel pressure.
my 96 doesnt like the timing advanced past 11, or there is some pinging. it does run better at 12-13 but 89 must be used. there doesnt seem to be any benefit advancing timing any further or higher octane regardless of timing.
11-05-2017, 05:10 PM
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95 F150 4x4 4.9L
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It has to be timing related. I tried working backwards on changes to try and trace it back. Installed motorcraft cap and rotor, regapped plugs back to .45, and installed stock coil. Still the exact same driving manors.
One other concern is the connector to the coil has a new wire, and a loose wire inside the connector. The new wire traces back to the ICM, which looks to be a replacement since there was an older once in my glove box when I purchased the truck. What would have happened to where the wires would need to be replaced?
One other concern is the connector to the coil has a new wire, and a loose wire inside the connector. The new wire traces back to the ICM, which looks to be a replacement since there was an older once in my glove box when I purchased the truck. What would have happened to where the wires would need to be replaced?
11-13-2017, 06:57 PM
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95 F150 4x4 4.9L
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Have not had a chance to mess with timing. I have been driving it in it’s poor state.
Owner I bought truck from said motor may have been rebuilt. I used the timing mark on balancer furthest outside. They seemed to match up with the timing notches on block. I may try to adjust timing with vacuum gauge until I can confirm the timing marks are set correctly.
I got a digital code reader to check engine codes, and a new fuel filter in the mean time.
Owner I bought truck from said motor may have been rebuilt. I used the timing mark on balancer furthest outside. They seemed to match up with the timing notches on block. I may try to adjust timing with vacuum gauge until I can confirm the timing marks are set correctly.
I got a digital code reader to check engine codes, and a new fuel filter in the mean time.
