Wont rev past 1800rpm but MAF is OK on ..

You need to......

....develop a plan of eliminating suspect components.
You seem to have made a reasonable effort to identify the cause/s.
You must have had something apart to suspect rags being ingested into the turbos????
Do you have access to ConZult or similar?
Is the engine compression OK?

 

Yes. When I got the car it was in pieces.

Thanks EastCoast. When I got his car it was in pieces. I got boxes of parts someof which were not from the car. I did not want to go into every detail in the post but I now need to.

Intake pipes to throttle body and turbo to intercooler pipes not installed. No radiator or piping installed. One exhaust pipe installed but no muffler installed. The other exhaust pipe was not there at all.

To get the car started I had to trace all the coil pack wires from the PTU to the coil packs. Number one coil plug was plugged into the VTC solenoid. The VTC plug was plugged into the No 1 coil so this fried the coil which I have replaced.

When it first started I could not rev the engine past 2000rpm.

As reported
Replaced ECU.
Replaced MAF
Checked all MAAF to ECU wiring and associated voltages
Boost leak tested. No major leaks.
Compression tested. One cylinder low - 60PSI. Others within specs.
Series 2 PTU had been installed. PTU Tested as per FSM. OK. Wiring tested . OK.
TPS tested . including Idled switch. OK.
CAS must be working as car idles smoothly at times. I cannot see the CAS causing rev limiting but all injectors are firing so I do not suspect CAS.
Fuel pressure checked. A little low. 39psi. Pushed pressure up to 45PSI. No change to rev limit.
Spark plugs removed for Comp check. No obvious issues.

DTC - 55

So with all this I have deduced a mechanical issue. ie - blocked or restricted intake. Cannot easily test exhaust pipes but exhaust is flowing out of them at 2000rpm.

Rob
I will put a vacuum gauge on and see the reading. I suspected the boost sensor was leaking so plugged it up for now.

So what is the best way to check if the turbos are seized?

MichaelZ

 

60 psi?

Don't you think a cylinder with 60 PSI is an issue?
The motors junk!
You'll need to determine if it's an issue with the valves or piston/cylinder bore.
If it's valve/s, then it's a cylinder head off job.
If it's piston or bore, then it's an engine out job.

 

I am currently driving a Zed with the excact same cylinder...

Issue and it is not dispalying the symptoms I am seeing.
With all due respect to your experience with these cars do you believe that one low pressure cylinder could limit the RPM of the vehicle? If so how?

My thinking is that a restriction in the intake system would reduce air flo regardless of the throttle being completely open (WOT) which would then not register in the MAF and would not alter injection pulse width hence limited revs. As stated all electronics seem to be as FSM specs and replacement of both MAF and ECU resulted in no change to the issue.

MichaelZ

 

20 inches vacuum on idle and

hardly drops when I open the throttle. Maybe down to 15 inches at WOT. Could not get the vac down very much with the throttle. Nowhere near 0 which is what I expect when the throttle is opened fully. I think that confirms my theory. Something is blocking the intake piping.

Any thoughts?

MichaelZ.

 

With the motor being in pieces, any chance of a mud wasps nest bocking something up.
You keep referring to blockages.
Just a thought.

 

Or.....

.....maybe it isn't getting enough fuel.

 

maybe you could put up a vid of what it is doing...

descriptions can be misinterpreted but if some of the more knowledgeable folks on the forum can see and hear what its doing it might help eliminate some possibilities

 

Although a twin turbo soarer, I had a turbo seize completely. Noticeable loss of power but the car could still redline without a problem. Do you have a wideband to see if it's going lean when trying to rev out suggesting a fuel issue or very rich when trying to rev to indicate a spark issue?

 

Will do tomorrow.

MichaelZ

 

For a quick way of finding if you have a inlet side or turbo issue just remove the hose from each sides throttle body to the inter cooler pipe near the radiator. Now get someone to rev the car. If it revs you have answered the direction you now need to check ( inter cooler area ?) also if it revs and the turbo's are working you should get an increase in pressure from the intercooler side. Also you don't have a single front mount do you as some guys have hooked them up in correctly. Also low compression or a dodgy turbo normally won't stop a motor reving,
Cheers
Dave

 

This car does have a FMIC which I had to pipe up. I will check the piping again.

MichaelZ.

 

Best suggestion so far!

With the hoses removed, you can also verify that the butterflies are opening correctly.
In addition, perhaps spray something like 'Aerostart' into the throttle bodies, which will have the same result as adding fuel.

 

Problem solved. Intercooler piping incorrect.

Thanks to all of you for your insights but I was right that it was not electrical and twin terror was spot on. FMIC pipes were on the wrong way on one side.

Some thoughts on the electrical side. Most car owners of modern cars seem to think that the electronics of a vehicle will be the most likely cause of any issues. I think this is because it seems to most to be a black and mysterious art. The truth is that today's cars are more reliable because of the electronics.

Trying to fix cars requires diagnostic skills and some electrical background. Fixing by replacement without any diagnostics is both time consuming and costly. Listen to the forum members and try to test first before buying major electronics especially.

Thank you again to all of you for your assistance.

PS. I bought the car for $1000. Was not running at all.

MichaelZ

 

Why does this happen?

Now that i have fixed the problem I need to know why? I suspect the piping needs to be crossed ove on one side because of the the way FMIC are made.

Is my diagram below correct? The turbo compress and suction sides may not be correct but is this the reason why the piping needs to be crossed over?

MichaelZ