Engine/Transmission (1994 - 1998) Need help, I can't figure out egt problem.

[12V Ford]

I have an egt problem that I can't figure out. They are way too high! I have PDR towing twins, both new turbos and the 35 has a 14 cm modified wstgate. 10 plate and 0 plate show the same boost and egt issues. I have pressure tested the system and found 0 boost leaks. Fuel filters are new(less than 200miles), new PDR overflow valve, new 1/2" fuel lines, no prefilter/heater(line goes from tank to fuel/water sep filter to lift pump), was having low fuel pressure when pedal was mashed, but my gauge is bad now, so I can't check that until the new one comes in. Air filter only has 7k on it. Have straight 5" exhaust.



Drive pressures have been about 1 to 1. Anything about 25-30 psi is over 1250 egt and max boost of about 55-57 is 1500egt, 28 psi ht3b and 27 psi hx35 and 60 drive pressure. I don't have blowoffs.

Even in valet mode, max boost is 40 psi and 1300egt. Egt gauge moves alot faster than the boost gauge. This is all unloaded. Smokes at low boost but clears up at about 25 psi. If I mash the pedal, boost is kind of slow to come up and when it does, egts are already over safe level.



Motor looked good when i put a new head on about 8k ago. Water temps are 170, oil press is 20-25 idle and 55 crusin. Motor used to run great when I had the stock turbo and 12cm, but wastegate was set too high I think(maybe 35 to 40 psi) and then I ran turbo with wastegate flapper unhooked for 400 miles and then forgot to hook gate back up and turbo was overboosting. I was having egt issues after that and thought is was a bad turbo. Stock turbo seals went out and that's when I went to the PDR35, but that didn't fix the egt issue.



The only thing I can fiqure is bad injectors, bad injector pump, bad lift pump or wastegate not set right.

Any ideas? I've been reading for the last 2 weeks and trying to figure this out for 2 months. Sorry so long. Never had the problem before with the stock turbo until I started messing with the wastegate, but it seemed to be set to start opening at 35 to 40 psi as far as I can remember.

 

[tp0d]

Whats your timing set at? You didnt mention that in the above... Sounds like it may have slipped. . are you gettin any white smoke?

Where are you sensing boost? directly at the manifold below the grids?

hmm. . tough problem

-j

 

[JTroiano]

Have you tried wiring your waste gate closed and see what happens? It takes 5 minutes. If your boost gets to high take your foot out of it. See what happens.



Jon T

 

[12V Ford]

Well, I think I'm starting to get it figured out. I screwed my wastegate rod in a full turn to make to gate open later and my egts went way down. Now it doesn't hit 1250 until 40psi and spool up is better.



Max boost is still 55psi, 27 max on ht3b and 28 on hx35. I may adjust the wastegate up some more and see how it does.

Anyone know what max boost I should run on the HX35?



I would think that the later the wastegate opens, the more max boost it would make, but it is stuck at 55psi and the smoke is all cleared up. I think I'm running out of fuel at the top end. What do I do about that? Like I said, before the fuel pressure gauge took a dump, it was going down to below 10 psi on WOT.



Thanks for the help already. Oh yeah, my timing is at 16* and total boost is sensed at the intake on the head.

 

[12V Ford]

Another thing to add. When I dynoed my truck with the stock turbo, the e-clip fell off and the wastegate was just blowing open, but it made around 58 psi and boost didn't even start until 2200rpm. I didn't have 2 boost gauges then, but I'm guessing the ht3b was pretty much making all that boost. Then when I discovered that, I put a new e-clip on, but forgot to hook up the line to the wastegate and it made about 60psi and spooled up fast. Again, 55-60 psi is about max because of no fuel(I'm guessing) no matter how the wastegate is setup.



Should I be measuring total boost at the hx35 or is the pressure drop at the intake not that significant?

 

[JTroiano]

THis is what I wrote on the other EGT thread.



"I even have the same timming. Somebody said that maybe the timming slipped? Also I dont have an AC condensor in front of the intercooler. How about a dirty radiator. Not enough air flow.



I do not have a waste gate on the the system. I was told I could adjust the boost with the amount of fuel. When I do add more fuel I will hook up the waste gate and will have to deal with the higher EGT's.



If you are using a waste gate. Is the drive pressure pushing the valve open early?



On my other twins on my 24 valve I just used the spring pressure on the waste gate to control the boost. The drive pressure would open the valve and I tightened or loosened the spring until I had it set were I wanted.

Probably not the best way but it is still working perfect 4 years later. "



Jon T