Just installed a new rebuilt engine in my 1995 F150. I purchased the engine from an Automotive Machine Shop up in Maine. It's only firing on 4 cylinders. I'm going to do a compression test in the morning. The cylinders that are missing are 3754. The engine is firing 2 cylinders then skipping 2 cylinders. Fires 1, no fire on 37, fire 26, no fire 54, fires 8. I am getting spark to all 8 cylinders. Any ideas or opinions before I dig into it in the morning?

 

Have you been in contact with the machine shop? They will probably have some suggestions since they will have to provide warranty service otherwise at some point. Was it a long block aka "crate motor" with all the trimmings?

Make sure too you've followed carefully all of their requirements to be eligible for warranty service. For example, while this doesn't apply in your case, new water pump and radiator, things like that. Otherwise they might say "too bad so sad".

 

Is your truck MAF or SD?
Who actually did the engine swap?
Was there any engine wiring besides the original used?

 

It is warranted for 4 years 40,000 miles. This truck has been my back burner project for 2 years. I've just been doing a little here and there, along the way. I am a Disabled Veteran, and I have not been in any hurry with this thing. I've had a lot of Dr. appointments this year. I just bought the engine in September. I bought it as a long block. Had to use my oil pan, timing cover, valve covers and intake. Over the past year, I have replaced seals in the front differential, replaced all the front suspension and steering parts. I put a new radiator in it. New water pump, new power steering pump. Lots of new parts. I want to do a compression test on it, before I contact the machine shop. I don't want to contact them, until I know for sure that the problem is theirs. It strikes me kind of odd, that the 4 cylinders that are missing, are directly across from each other on the distributor cap.

 

It is MAF. I did the engine swap myself. I am a mechanic by trade. I was a mechanic in the military, and I worked for Chrysler for 5 years. Only new wires are the spark plug wires. Engine wire harness is all original. I did put a new coil on it.

 

OK good info there. Was the reman engine supposed to be a direct replacement for a '95? Have you tried the old 302 firing order on the plugs? If the motor has a cam with the old firing order in it it still won't run correctly with the spark plugs revised because the injectors are fired sequentially too, but it may run a bit better and then you will know. You then have to decide what action you want to take to fix it.

 

Not real familiar with Fords. Have been partial to Dodge all my life until about 4 years ago. I decided that Dodge was to expensive on gas. Anyway, I did not know there there was a different firing order for the 302. You said older. How much older. I went by the firing order that was on a label on the truck. I have to look in the repair manual for another firing order. The people I got the engine from, knew I was getting it for a 95. There was 2 things different though. First the heads were different. I found out the hard way. My original spark plugs were Autolite 25 copper. They wouldn't work in these new heads. I had to buy Autolite 764 copper. Which were listed for 5.8L. Come to think about it I think I did see them list for 86 and older 302's as well. The second thing different was....Everything about the 2 blocks were identical except, on top of the block in the rear there is a hole (where the oil pressure sending unit used to be on the older engines) On my original 95 model 302, there was a Knock sensor screwed into that hole. On the engine that I bought, the hole was there. Same hole same location. But it was not threaded. I had to tap some threads in it in order to install my knock sensor.

 

Thank you so much. I just went back out to the garage and looked in the manual and changed the spark plugs around. I had to swap 3 with 5 and 7 with 4. It runs much smoother now, and I can tell that it is firing on all 8 cylinders. Now, it runs smooth when it first starts, and as it idles a little bit, it starts surging, and all of a sudden the timing is way advanced. Can't tell for sure, probably about 20 or 25 BTC. And the timing mark bounces instead of being steady. What kind of action, are you talking about taking, to fix it?

 

Well F&c'in A, that's a good start! Glad somebody could help, cuz it sure wasn't me.

 

So basically, through all this homework last night, the conclusion is, I have a MAF truck with a SD engine. So now, how do I make the SD engine work in my truck? Am I going to have to buy a different computer?

 

Did you check timing with spout connector taken off ? I would first be focusing on the timing then go to the next step of SD vs MAF. Factory base setting is probably 10 degrees, most guys here go to 12 to 14 and listen for pinging, then back it off. Actually MAF is the better system so once you get it running right you'll be happier. With MAF you could go with a bigger cam for better performance. I have the opposite problem at the moment ....

 

No, I didn't pull the spout connector when I was timing it. Is that my problem? I'll do that first thing, when I get home this evening. Thank you.

 

Yes, by not removing/pulling the SPOUT connector, you can't set base timing and the PCM continues to adjust.

 

I pulled my SPOUT this evening and timed my engine to 10 degrees BTC. Shut off the engine. re-inserted the SPOUT, and started the engine back up. It sounded so good. I am a disabled veteran, and I can't do anything else to the truck until I get my next check on the 1st. The next thing to do is to get it legal and take it down for a front end alignment. Anyway, I let it idle for at least half an hour, then drove it around in the yard a little. It started idling way down, and died a couple of times as I was backing it back into the garage. When I start the engine back up, the timing is on 10* BTC and the mark is steady, then sporadically the timing will advance probably 15* more for a few seconds, then back down to 11*. Through all of this, the timing mark is steady.

 

It may be that the cam is too radical for fuel injection, even MAF systems have limits with a stock computer. If you have a vacuum gage, take a reading at idle. It should be at least 14 inches I believe. Get much lower and things can get thrown off, idle will surge etc. I've seen a stock truck computer run with an e303 cam , but it didn't like it.

Also thank you for your service.