96 Tow Truck M5, just a pooch!

[OneSlowTow]

First time posting, so "HI!". There got that out of the way.

Anyways, the majority of the posts by 'me' are not the truck owner. I'm his computer guru friend, but I am also a car nut so fear not! He's a big mechanic as well. Just to get all the FYIs out of the way!

(M5 5spd btw) We're not quite sure what's going on with the truck, it's just gutless. And while it is quite heavier than your avg PSD due to being a Tow Truck, but this slow just doesn't seem right. The oddest bit, is that there seems to be no change in performance with the Superchips programmer that a friend gave him. Few days ago I replaced the EBV sensor and pipe, since the pipe was plugged solid (no surprise!). Then we made a 10K mod (we decided to go with 6.9k since people reported down to 5.6k before idle problems) and installed it today with the tune set to stock. Small bit of smoke, compared to virtually non any other time. Stopped and tuned it to 'performance' and smoked quite a bit, but in the upper Rs (probably 2750-3K+) it was gutless. There was a noticeable change in the exhaust tone as well, it was kind of raspy.

Short of going out and driving it again to get these numbers, all I can tell you is that the MAP PSI is around 28 and khz around 110-125. Highest boost we saw was 16psi.

Mods so far are just a straight pipe, kicked out mid-box through a 3" can. The 10K Mod (again we did 6.9K).

Replaced the EBV stuff as I mentioned, and the CPS. 4 new injectors with the other 4 tested and were good. Glow plugs replaced. Harnesses for the glow plugs and injectors were replaced, as they were not in good shape. He told me there's such a list that he can't even think of it all right now But if you think of anything I'll ask if it was done.

I plan to do the regulator screen cleaning and the BB spacer. I'll see if he wants the regulator rebuilt since it looked cheap ($15-30). He's asked me to make a list of stuff to buy for performance, but I have a feeling there should be other things done first before that. I managed to talk him into doing the free mods first, and then progressively get more expensive. Found a 3" mandrel down pipe for $89 so that's on the list, and to make a better air intake with the bigger NAPA filter. Plan to do a mechanical "MAP fooler" to blow off pressure over 20psi (or less if you recommend it). The TW chip is on the list after all that, and he really would like to slap a turbo on it too and we found a nice place on eBay that has the Garrett ones for $550 (shipped), non waste gate model with ported and polished inlet @ 1.10 A/R, Banks compressor wheel, 1.15 A/R turbine housing with the stock turbine wheel. No core charge so that price is what it costs.

Only question, obviously above the "wtf is wrong with this thing?", is the downpipe. It all shows a single down pipe, but when we had this thing in the air removing the muffler, there were 2 of the flattened pipes, on each side of the motor. Do you remove all of that, and then it's a single 3" down pipe? If so, how can that be better than 2x 2.5"? And then is the exhaust back 3" or 2.5"?

Thanks for bearing with me on this!

[OneSlowTow]

So, of 27 people, no one has a clue?

[lwillson]

Have you checked the fuel pressure? is it still the original fuel pump? There is a good chance you have a weak pump.

[adfields]

Two down pipes??? Is it twin turbo? How is the thing plumbed into two down pipes?
Fuel filter, intake boost leak, or low compression is what jumps out at me.

[Powersmokein]

ummmm hell I dunno what to tell ya

[OneSlowTow]

I'll try and get some pictures on the exhaust, again though this was a couple months ago so I could easily be wrong heh And no it's a single Garrett TP38, which I noticed has some slight dusting. There's a few nicks in the compressor impeller.

I'll try and get some fuel pressure too, no guarantees on that one though. Did the fuel pressure regulator mod and that was no help either. I completely forgot to do the screen cleaning though, I'll try to find the info on that again and knock that out of the way.

Is the MAP PSI supposed to read the same as the Intake PSI (Boost)? Because when we had the scanner hooked up the one day, the MAP PSI was much higher than the actual boost.

I'll edit with new info.

EDIT: OK Forget the exhaust. What I was seeing was the cross-over for the driver's bank to the turbo and I remember seeing heat shield foil, like what's on the lovely squashed down pipe. So yea, just me being a retard there!

Fuel pressure will have to wait till the powersteering stuff gets finished since the steering shaft is unhooked and I've been informed that it'll blow the airbag if I turn the key on heh

For anyone interested, here's the compressor wheel. Not as bad as some I've seen as avatars, but bad enough to cause performance issues? Also, there any crank filter deletes? The inlet tube is quite oily.

[adfields]

Not 100% sure on the MAP vs Boost, but I'm thinking they should be close. Oil on the outside of the inlet tubes is a sign of boost leaking off. Oil on the inside is Ford's stupid crank case vent design, there are mods to fix it if its bad.

I'm still thinking it's leaking the boost pressure off some place and robbing the power. Such a leak is hard to find as it may only leak at higher boost psi's and that is hard to replicate when your under the hood.

[OneSlowTow]

Originally Posted by adfields

Not 100% sure on the MAP vs Boost, but I'm thinking they should be close. Oil on the outside of the inlet tubes is a sign of boost leaking off. Oil on the inside is Ford's stupid crank case vent design, there are mods to fix it if its bad.

I'm still thinking it's leaking the boost pressure off some place and robbing the power. Such a leak is hard to find as it may only leak at higher boost psi's and that is hard to replicate when your under the hood.

Well hells bells. Thanks for the info, and I'll relay that to him. I found it bizzar that Ford would stick a huge restriction in the inlet tube like that, but... guess that's for ya!

I wouldn't be surprised of it leaking boost with how his orange boot looked and was a bit torn under where the hose clamp sits. I still find it funny he tried telling me he just bought that and it's new It would take a receipt and some other visual confirmation on that boot to convince me!

As for the MAP, anyone know how many BAR they are? They just a 2 BAR or a 3? I was thinking maybe buying a 2 or 3 BAR GM, and wiring that in, since the Ford one is like $130

OH! And the fuel pressure is around 65-73. Can't really tell since it bounces around between the all that :|

[adfields]

Originally Posted by OneSlowTow

As for the MAP, anyone know how many BAR they are? They just a 2 BAR or a 3? I was thinking maybe buying a 2 or 3 BAR GM, and wiring that in, since the Ford one is like $130 |

I'm no electronics guy so not a clue on the kind of MAP it has. So hear is a for that question.

The orange boot tarring near the clamp is a very good clue of a leak also. The motor oil from the crank vent softens the rubber and sooner or later the leaking starts.

Sounds like normal fuel PSI