1981 f250 Coachman (motorhome) I6 timing issues Need HELP

[NewEnglandF250]

First I would like to thank everyone on here and Gary for this awesome collection!!! Well done!!!! Im new to the bullnose community and am having trouble adjusting my timing. it was popping on hill on the way home from buying it........I bought the camper to restore and Im well on my way to being done......now I'm turning my attention to the motor. It has 42,000 and is stock. yfa 1 bbl carb etc...it looks like the ignition module/coil? was replaced due to not having the "yellow and black" wire's that the Haynes manual says.....

Haynes manual says.......

" If the vehicle is an early California model with an inline six-cylinder engine with MCU-controlled Duraspark, disconnect the vacuum advance hoses and plug hoses. Locate the Duraspark module and disconnect the Yellow and Black wire connector. Jumper the Yellow and Black wires together on the module side of the harness. Note: Jumping the pins overrides the ignition module. Accurate timing measurements can only be made in this mode."

Q: more than 1 hose? location of those hoses? I know one of them is coming off the distributor

Q: Yellow and Black wires? what other color could the be? I'll check tomorrow to see what ignition it has but I dont want to jumper the wrong wires.

Any help would be greatly helpful!!!!

 

[ArdWrknTrk]

Welcome to the forum!

Ok, you have a 1981 F250 with a 4.9l straight six.

We should look at the Ford Electrical and Vacuum Troubleshooting Manual.

Unfortunately, often the Haynes and Clymer manuals don't have the correct (or ALL the) information in them.

They are not discussing a normal DuraSpark II module.

If I go to "documentation"> electrical> 1981 EVTM> ignition> I'm seeing on page 32 that in 1981 only the 5.0 & 5.8l V8 engines have the California MCU.

if you need to set the timing of a DSII model truck all you need is to disconnect or clamp the vacuum line to the distributor.

Attach the timing light to #1 plug wire and chalk the timing marks found behind the crank pulley.

If the timing seems far retarded from spec (which is usually around 10* BTDC) then loosen the distributor hold down and see if you can turn the distributor clockwise.

Snug the clamp and check again.

I hope this helps.

[Rembrant]

Q: Yellow and Black wires? what other color could the be? I'll check tomorrow to see what ignition it has but I dont want to jumper the wrong wires.

Any help would be greatly helpful!!!!

The yellow and black wires bit is referring to the DSII ignition module with the yellow grommets, that was specific to the California models. See Ebay picture below...

https://www.ebay.com/itm/NOS-1978-1979-FORD-MUSTANG-FAIRMONT-GRANADA-DURASPARK-IGNITION-CONTROL-MODULE/362171666452?epid=1423300045&hash=item54531d1014:g:ESwAAOSwSrNaHgnR

However, as Jim mentioned above, sounds like the 300/6 did not have that module anyway.

The standard DSII ignition module will have a blue grommet, and two plugs/connectors.

 

[Gary Lewis]

Welcome!!!

Looks like Jim and Cory have you pointed in the right direction. Around here we like to use factory documentation instead of aftermarket. While there can be errors in the factory docs, there are far fewer of them since the Ford techs were to work from them. Having said that, sometimes the factory documentation assumes a level of understanding that might not be there, and the aftermarket publications provide.

As the guys have said, the blue grommet box is the standard DS-II box. And unless your truck was built to be sold in California or at a high altitude that's what it should have had on it. And no MCU.

So timing is simple - pull and plug the vacuum advance, loosen the lock bolt on the distributor, and with the timing light showing the marks on the balancer against the timing pointer turn the distributor to get the correct timing.

However, tell us more about the popping. Under what conditions? Going up a hill or coming down? I ask because if it is under load, like going up a hill, it may be a breakdown in the plug wires, or a bad plug. If it is coming down hill it is more likely due to carburetion.

[NewEnglandF250]

Welcome!!!

Looks like Jim and Cory have you pointed in the right direction. Around here we like to use factory documentation instead of aftermarket. While there can be errors in the factory docs, there are far fewer of them since the Ford techs were to work from them. Having said that, sometimes the factory documentation assumes a level of understanding that might not be there, and the aftermarket publications provide.

As the guys have said, the blue grommet box is the standard DS-II box. And unless your truck was built to be sold in California or at a high altitude that's what it should have had on it. And no MCU.

So timing is simple - pull and plug the vacuum advance, loosen the lock bolt on the distributor, and with the timing light showing the marks on the balancer against the timing pointer turn the distributor to get the correct timing.

However, tell us more about the popping. Under what conditions? Going up a hill or coming down? I ask because if it is under load, like going up a hill, it may be a breakdown in the plug wires, or a bad plug. If it is coming down hill it is more likely due to carburetion.

Thank you all very much! I was scratching my head trying to figure that out ..... I will ditch the aftermarket book. I’ll set the timing and give you guys an update. Gary the popping/pinging was going up a hill under load.... it’s a 4 speed manual so I was in 3rd climbing it. It was fine on flat roads but did pop/ping on hard acceleration....I had read on a forum that it could be timing related so I went that direction....I changed the plugs, wires, cap rotor....

[Gary Lewis]

Thank you all very much! I was scratching my head trying to figure that out ..... I will ditch the aftermarket book. I’ll set the timing and give you guys an update. Gary the popping/pinging was going up a hill under load.... it’s a 4 speed manual so I was in 3rd climbing it. It was fine on flat roads but did pop/ping on hard acceleration....I had read on a forum that it could be timing related so I went that direction....I changed the plugs, wires, cap rotor....

If it is under load at part throttle then it is probably too much initial advance. But, has someone disabled the EGR system?

[1986F150Six]

Welcome to the forum!

if you need to set the timing of a DSII model truck all you need is to disconnect or clamp the vacuum line to the distributor.

Attach the timing light to #1 plug wire and chalk the timing marks found behind the crank pulley.

If the timing seems far retarded from spec (which is usually around 10* BTDC) then loosen the distributor hold down and see if you can turn the distributor clockwise.

Snug the clamp and check again.

I hope this helps.

Jim, you are used to doing magic on a V8. The little "torque monster" six cylinder has timing gears, not a chain, so turning the distributor clockwise retards the timing.

 

[ArdWrknTrk]

Welcome to the forum!

if you need to set the timing of a DSII model truck all you need is to disconnect or clamp the vacuum line to the distributor.

Attach the timing light to #1 plug wire and chalk the timing marks found behind the crank pulley.

If the timing seems far retarded from spec (which is usually around 10* BTDC) then loosen the distributor hold down and see if you can turn the distributor clockwise.

Snug the clamp and check again.

I hope this helps.

Jim, you are used to doing magic on a V8. The little "torque monster" six cylinder has timing gears, not a chain, so turning the distributor clockwise retards the timing.

You're absolutely right David!

Thank you for pointing out my mistake.

I hope that the OP sees this and understands the implications.

[NewEnglandF250]

If it is under load at part throttle then it is probably too much initial advance. But, has someone disabled the EGR system?

Gary, I'm not sure....I take a look

[ArdWrknTrk]

Gary, I'm not sure....I take a look

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