Engine seems flat 3.2

[ALXinNZ]

Hi Team

I have recently felt my car is running a little funny. It has a 3.2 in it,Motronic, SW chip, and hasn't missed a beat since a full rebuild 20 000 miles ago. It is a strong motor very responsive usually.
It has gone off song. I can hear it when driving the exhaust note is off and it is bugging me. just seems to be running flat
compression test found all cylinders were equal
bosch platinum 4 plugs are all nice and have same colouring
exhaust temp is close enough at each outlet
rotor test ok
leads test fine
It is as if the timing is retarded or something.

Just looking for some ideas or a place to start.
Valve adjustment?
Fuel pump?
Reference sensors?
Air leak?
Where to start???

Thanks for your time

Alex

[Arne2]

I've never had good luck with platinum plugs in cars of that vintage. May not be the problem, but I'd go with a good set of copper plugs, either Bosch Super or NGK.

Past that, no input, but I'll be interested to follow and see what you find.

[faverymi]

Vacuum leaks were really killing my engine's performance.

Something that I overlooked for a long time.

[TT Oversteer]

^^^^^^^^ What he said.

Yes, check for vacuum leaks, especially the rubber coupling that joins he two intake manifold halves. Mine was swollen from age and leaking badly with no visible signs of a problem. Spray some carb cleaner in this area and check for rpm change at idle.

[msterling]

+2 on the intake leak. My intake manifold was loose. It is easy to snug up the fasteners. Mine ran and sounded much better after this simple fix.

Go with copper plugs.

How many miles? Your catalytic converter could be failing and causing excessive back pressure.

BTW your 3.2 IS flat (a flat six)

[gliding_serpent]

great looking car!!!

[ALXinNZ]

Thank you everyone.
I will start looking down the intake leak side of things.
New NGK's ordered from our host as they are $30 each here ( conversion about $16 each ) so a massive saving. Just a week away.
No emission gear on the car regarding catalytic converter blockage.
Will also do a fuel line pressure test while driving under load.
As for sounding FLAT being a Flat 6 it is quite loud
https://www.youtube.com/watch?v=P0i-MpDylE4
Reason for rear bumper missing is that it caught fire the previous day on the track so I cut it out with a saw blade and kept going.

[Chuck.H]

I've heard (but haven't tried) a good way to check for leaks w/o a smoke machine is to light up a fat cigar and blow the smoke into a vacuum tube connection, like maybe the one at the base of the throttle body.

Chuck.H
'89 TurboLookTarga, 387k miles

[Quicksilver]

One testing point:
Get an IR thermometer, put the car up on jack stands, fire it up while cold and measure the individual exhaust ports as it heats up measure the temp of each port. If you have cold port(s) then you have something to chase.

Also...
Vacuum based issues should have no effect on full throttle as by definition full throttle has no vacuum.

[ALXinNZ]

Thanks guy's.
I have checked individual port temps and they are even
New Plugs and issue is still there.
Moving down the list
Will keep you posted


Regards

[timmy2]

Tried a different SW chip yet?
They are not infallible.
Other than that have you gone the full 20,00 miles since the rebuild without a valve adjustment?

[ALXinNZ]

Ok
I think we are getting somewhere
Reference sensor checked with Bentley Manual numbers and look ok
However when I checked the Speed sensor pin 1 & 2 read fine but no signal from the 1 & 3 and 2 & 3 pins. So faulty pin 3 wire I would say. The kicker is that the car wont start with the speed sensor unplugged but will start with it plugged in. Even with the pin three fault. I re checked the pins with my meter after the starting and still no signal shown on the readout.
Re checked the reference sensor and all seems fine.
???? How many wires does the speed sensor need? ( does it look for any signal )

[Chuck.H]

IMHO, it's hard to have a motronic ignition problem that just retards the advance to cause a loss of power; any reference or speed sensor problem would be catastrophic or cause significant jerkiness.

However, if it's running a little rich that could cause it to feel sluggish, so might be worth checking the CHT sensor and AFM. The AFM contains an air temp sensor that if off could richen the mixture.

Do you have an A/F meter available to check the mixture?

Best,
Chuck.H
'89 TurboLookTarga, 387k miles

[JeremyD]

Cylinder Head Temp Sensor. (In a bad location) and go with copper plugs.

ALSO - check your throttle linkage - if you are not engaging your wide open micro switch - that can cost you about 15-20 HP.

How old are the plug wires? Coil? I've found that the coil's that are out these days are mostly crap

[ALXinNZ]

Ok Thanks again for the thoughts.
New copper plugs, still same.
fuel pressure seems fine at idle and at high rpm but have not taken for a run yet.
no air leaks found yet
reference speed sensor pin 3 fault ??
ordering new rotor and cap, fuel filter, valve cover gaskets and reference sensors from our host now. have AFM out tonight and have a good look at the ICV while there. Cheers everyone

[m110]

original cat?

[ALXinNZ]

Here is fuel pressure test. Noisy valves.
Thoughts??

https://m.facebook.com/l.php?u=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv% 3Df99Ij_NVHcU%26feature%3Dyoutu.be&h=1AQHF1PNx&enc=AZN878crbgmTzTOdY9nceuTwDv2JnbEaQTEQ_2ZyJZgaST WlqTFD7aiIwVaA-sJAHUU&s=1

[ALXinNZ]

Ok tested everything I can think apart from the actual injectors. Waiting on parts now before i pop the valve covers off and check the clearances there, will do a full service. Will replace one thing at a time and go for a skid to see if I can pin point the issue. Still have no reading on speed sensor pin 3. everything else tests OK
Thanks for the help.

[yelcab1]

I think I know the problem. The body work is all wrong for a 3.2L engine.

[strudelwagon]

Looks just right to me!