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davehop, Ford Technician
Category: Ford
Satisfied Customers: 1291
Experience:  Fully certified in all phases of automotive repair as recognized and certified by Ford Motor Company
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Ford F150: fORD f150 Timing set at 10 degrees BTC. Ideals

Resolved Question:

fORD f150 Timing set at 10 degrees BTC.
Ideals low... What should the Idle RPM be?
Also, when steppng on gas it runs okay... when you left off gas to cost at 30 or 40 MPH the truck shakes (Motor)?

Yesterday truck ran fine except for when you stepped on the gas to get on the freeway it had a 2 or 3 second delay
Submitted: 4 years ago.
Category: Ford
Expert:  davehop replied 4 years ago.

davehop :

Hello and welcome to JA, the idle should be 750 rpm =/- 25 for automatic trans and 750 rpm =/- 25 for manual trans...when you are checking the timing, make sure the spout connector is unplugged....the symptoms sound like the IAC valve is sticking...with the engine at idle, unplug the IAC valve, and see if the RPM drops, it should be affected when the IAC is unplugged, if it does not change, then the IAC needs to be replaced.

Customer: OKay thanks, XXXXX XXXXX with truck before I received the answer last night. She will be bringing it over today. I didn't know you had to disconnect the IAC Calve connector when you set the timing.... must have overlooked that in the manual.... However when it was running ruff, i did disconnect it and the RPM's went down... Will do what you suggested today....
davehop :

no you do not have to disconnect the IAC to set the timing, you have to disconnect the spout connector, this is a little plug right next to the distributor. The IAC needs to be unplugged to verify that it is able to control the idle. Recheck the timing with the spout unplugged and let me know...

Customer: Okay.... They just arrived..... I'll go look for it....
Customer: Went outside and looked around the Distributor... This Distributor has a rectangle plug that comes off it.... then in that same wiring harness is two wires that comes out and has a cap on it. The cap has two connetor pins that appear to complete a circuit... is this what you are refering to? Do you have a picture of the Sput Connector.... looking for a picture of it. Thanks
Customer: Oh MY Gosh.... Head ache...
Customer: My Daughters truck is a 1990 Ford F150 5.0 with an AOD transmission in it. The transmission ewas going out and her engine thermastat cover leaked... so they bought a 1992 F150 with a 5.0 and an automatic transmission in it.
Customer: We swapped the motor and transmission. everything ran great the first three days... then it started this motor vibration. Disconected the battery, pulled the Spout connector, put the battery cable back on and set the timing at 10 BTC. put the spout plug back in and it improved a littlebit. It still shakes when you try to keep it at a steedy speed (between 30-45). The following also happened on the test drive, started truck and the RPM was almost 1000 and then kicked down to 700 to 750 rpms (Flucuated) Put it in reverse and the RPM dropped to 650 RPM. Driving from a dead stop it shifted into 2nd gear at 15 MPH at 2000 rpms, 3rd gear 25 MPH at 2000 RPM and 4th at 45 miles an hur at 45 MPH... Could go any higher, in residential area. Upon returning to the house put the truck in park and it stayed at 1000 rpms. Turn the truck off and restarted it and it idled at 750 RPMs. ANy suggestions? We didn't replace the spark plugs or the wires because the other truck ran fine, (I never drove it)... Will replace plugs and wires from old motor that was working okay to eliminate that problem... will also check all the wires going to the fuel injectors to see if they are connected.... any suggestions would be appreciated.... When we traded out the motors, i had to change the wiring harness... forgot to mention that... 1992 had a square head the wires all connected to, and the 1990 ford had four seperate groups of wires that connected on the firewall. Do you think i need to change out any computer modules etc...
davehop :

The PCM should stay with the engine, so take the PCM from the donor truck and put it in the truck the motor was put into, then recheck

davehop :

yes, the 2 wire plug is the spout connector

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