Boost Problem.

[Fred]

85.5 SVO

Rebuilt the motor with factory parts to factory specs, rebuilt injectors and turbo. **The motor has just reached it's breakin point, replaced fluids.

Parts replaced: TFI, stator, cap, rotor plugs and plug wires, all turbo hoses including oil supply and return line, all gaskits, intake and exhaust etc, fuel filter and exhaust manifold.

Parts tested and calibrated: Fuel switch, fuseable link and TPS.

Parts not replaced: Boost control, coil and fuel pump.

Problem: When I punch it, I have 4 lbs of boost max and after 3500 rpm motor bogs and total loss of power. I can never exceed 4000 rpm. The motor just will not exceed 4000 rpm even if I gradually speed up and thats in any gear!

*With "no load" car in neutral, i can redline it.*

Question: Can the parts not replace cause this major decrease in performance?


Totally Spent!

[Ralphcobra]

I had a similar problem on 1 of my cars. I looked forever. Finally found that althought I had replaced the fuel pump, it wasn't properly grounding and the car would not rev up while driving. I replaced the new pump with a larger 255, grounded it on the frame near the tank and my problems went away. Hope this could give you some guidance, althought I am certainly no expert. Ralph

[SVOJEFF]

Boost problem?

I had the same problem. check your vain meter wire plug. I had a wire broke at the plug so was real hard to see! Just my 2 cents worth! Don't give up just keep us informed with info we all can figure something out!

[Fred]

Im not familiar with "vain meter wire plug" can you help me locate it. What am I checking once I locate it. Voltage or ohms, or both?

Thanx....

[Fred]

What make/model fuel pump would you recommend and a source to purchase it. Im in the Nothern California/Bay Area.

Thanx.....

[kiwi]

Fred

Check your Air Vane to make sure its not backwards (the 'door' should move towards the turbo).......
-Its the 'controlled' doorway leading to the turbo inlet right off the air cleaner/check that plug per Jeff too..........

[notopstang]

walbro

The fuel pump usually recomended here is the Walbro 255 lph pump.

See section 5 here:

http://www.svoca.com/forum/showthread.php?s=&threadid=1638

good luck
--Javier

[SVOeric]

the symptoms do certainly sound like a fuel pump problem.

I used a bosch 255 lph pump -- if you are planning later mods it is a good idea to use the 255 high pressure. -- it's only a few bucks more.

Since you have a 85.5, you don't have the resistance wire for ground on the fuel pump, you do however have a little (about the size of 2 D batteries) with vacume going to one end, and a electrical plug on the other -- this does control fuel pressure, problems at high rpm -- what this little thing does is crank the fuel pressure UP when you are "romping" on it.

If you can't figure out what I am talking about, let me know, and I'll see if I can find a pic of it.

[SVOeric]

oh yea-- on your boost problem, sounds like the clip that goes between the waste gate, and the waste gate actuator may have come off -- You will have to look at this from under the car -- if you need more info, just ask.

(you're new, and I don't know how much you know)

[GAboySVO]

Here's the link to a picute of the thingy that SVOeric was talking about.

http://www.svoca.com/forum/attachment.php?s=&postid=8722

[Fred]

I bought the SVO in 86.

I pulled the motor twice since. The first time was when the turbo blew and head cracked at around 88kmi, I pulled parts had repaired and then I installed them, I left the bottom alone (block).

This time I had it rebuilt at a local speed shop. Long block rebuild. Factor parts built to specs and balanced.

I replaced drive chain when my diff detonated about 36 months ago, when it blew it took out the transmision seals and shook it up pretty bad, oh I was probably doing just under or around 100mph. I pulled the transmision and had it rebuilt while waiting for the diff to arrive then install them.

The did confirm clip that goes between the waste gate, and the waste gate actuator is in place and the fuel pump pressure control is plugged in. I was on this awsome formum oh 3:30-4am this morning reading up on all he differant symptoms and fixes before was ready to call it a night.

Is their a test for the Fuel pressure regulator thingy?

Can the coil cause this type of problem? It's oem! Same as the Boost control and the fuel pump.

[SVOeric]

ok -- the vane meter is right below the air filter -- make sure it is plugged in good. I made that mistake last year after dyno day -- it will run like crap when you try to accelerate.

the fuel pressure can be checked on the rail (the little nipple on the fuel rail iteself) and before the regulator (up next to the vacume tree, there is another nipple) -- I would check the line pressure first, as that is where you will see pressure drop first.

Another thing to try is make sure you have a good fuel filter -- if your car sat for a while waiting for the engine to be complete, some crap may have made its way into your filter, or gas tank.

And -- as always-- make sure you have good wires, and plugs -- the best basline is to always use motorcraft wires and plugs. -- if you want to try something else -- that's ok -- but you need to start trying new stuff after you have it running good.

As a general rule -- I would say the coil is not the problem -- But anything is possible. -- Coils are usually the type of things that work, or don't work at all.

I would also start checking the wiring around the TPS, and TFI module, and check your ground cables -- in particular -- the one that goes to the turbo, and the one that goes to the firewall from the bel-housing bolt.

Oh yea--- one other thing -- did they mill your block, or head ?? did your timing marks line up correctly when you installed the timing belt?

[Fred]

No mill work was done.

Yes the timing marks did lineup after a grueling 4plus hrs of frustration.

[SVOJEFF]

Boost problem!

Yeh i would check the coil! Mine was bad and i would have bet money that it was not the problem but guess what? It was a $15.00 part and made all the difference and on hell of a smile when fixed! Check it out might or not?

[Fred]

I will check/inspect/replace all items you guys suggest until I get this problem is corrected.

Thanx,

Fred