have my dak in shop for engine swap they put a 2001 4.7 into my 2002 they have tried everything, changed crank,cam sensors,fuel pump,plugs,coils,pcm,removed and checked engine harness, finally discovered tone wheel on cam different from 01 to 02 changed that, now will start but wont make power, max 3000 rpm runs horrible, they have burnt out 3 starters trying to make it start,have had ecm reflashed, still has p0340 code, has anyone heard of something like this, they have been working on this for 5 weeks now, i want to pull it out of there but trying to take this anywhere else now will be difficult

 

Hi Stubby,

Welcome to the forums. Sorry to hear about your problems. Most of us on this board know about it and try to warn people about the tone rings. You need to match the number of connectors on the PCM.

You said "tone wheel on cam different." Did they do anything with the tone ring on the crankshaft? It is different too.

Another possibility is your shop has messed up the valve timing. It's a bit more complicated on the 4.7 than most engines as it has 3 chains, not just one. If it's off a little, it'll run like cr*p.

The P0340 is "no cam signal." It could still be a bad camshaft sensor.

Keep us posted. Good luck.

 

not sure what you mean by matching number of connectors on pcm, pcm was changed but using pcm from 2002 truck, there is no way to get pcm from 2001 truck the engine came from, but i know they did not change crank tone wheel

 

just a question does the injectors and spark not get their signal from the cam sensor

 

How many connectors are on the PCM in your truck now? 3 or 4?

Both the crank and camshaft sensors are used for fuel/spark.

From the Factory Manual:
The signal from the CMP sensor is used in conjunction with the crankshaft position sensor to differentiate between fuel injection and spark events. It is also used to synchronize the fuel injectors with their respective cylinders.

 

there are 3 connectors

 

3 connectors is the JTEC computer, the "earlier" version. There shouldn't have been a problem with ONLY the cam tone ring. Both tone rings, crank and cam, change between PCM versions. The "later" version of the PCM is NGC. It would have 4 connectors.

The JTEC PCM has 16 tooth tone ring and NGC has a 32 tooth tone ring on the crankshaft.

On the camshaft, both are 30 teeth but the arrangement of the windows (triggers) is different between the two. Again, not compatible.

Pull the RH valve cover. If you see NGC stamped on the sprocket, it's the wrong one. There are NO markings on the JTEC sprocket.

Get more info out of them as to exactly what's going on.

It's either that or I expect they screwed up the valve timing.

 

i know for a fact the crank wheel was not changed, he does not work weekends, but you can bet i'll be there monday morning to insist it gets changed, he says that there is no difference but i would like to watch him change it, like i said he's had it for five weeks, pulling at straws to make it work, i'm afraid to see the bill, thanks so much for the info

 

Stubby,

Yes, they would have needed to change BOTH tone rings BUT odds are the 2001 was JTEC to begin with - that's why you look at the PCM before you pull it in junkyard.

I can't see why'd they only swap out the cam tone ring. Messing up the valve timing is still a possibility, sorry to harp on that. But really, it's different than other engines and these guys you have, well I just don't know.