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Old 11-07-2020, 10:22 PM   #1
jaychen
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Hi guys,

New to this forum, but not new to forums.

I have searched for hours and not found much in the way of helping diagnose my exact conditions or diagnosis for testing sensors. I'm hoping you guys might be able to shed some light on these things for me.

Background:

Car is a 1989 Australian delivered 740 turbo.

It has been converted to lh2.4 and has T04z turbo, green top injectors, 960 MAF, T5 gearbox, LC1, walbro255.

Unfortunately the car has had many owners before me and as such, is basically a basketcase.

Problems:

Lean idle (17.1-17.9 at idle - unplugging maf it reads 11.0)
Bogging under boost
Generally drives like crap.

Since the car was originally lh2.2, i believe it does not have on-board diagnostics.

Can anyone help with resistance/voltage values for correctly working:

TPS
CTS
Injectors
AAM (voltage values at idle)

The LH2.4 has a chip in it, but no visible markings on the chip.

Engine timing is correct, keyway has not sheared.

Initially when I received the car, the maf was post intercooler. I switched it back to the intake side and began fixing all vac/boost leaks with a smoke tester.

I recently changed the oxygen sensor but upon receiving my replacement, the plug on the engine harness was male, not female, so I had to utilise the old oxygen sensor plug and join the wires.

For some reason the thermo fan was also wired to the high beam headlights. Low speed was wired to parker lights and high speed to headlights on. I have rectified this and have it running on a switch from inside the car as the breaker (70a) that was initially used would trip every time I drove the car.

Needless to say the car has a fair amount of issues but I'm working through them to make it reliable enough to drive every day.

I have not checked compression or done a leakdown test yet, but will do so if it is recommended.
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Old 11-08-2020, 04:38 PM   #2
Lankku
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Because the current chip is unknown, I might start with a chip which is made for that combo. But it wont' hurt to do some measuring first. What is the AFR while cruising and under boost?

With 2.4 you have diagnostics if the wiring has been swapped/modified accordingly. If not, then you can add it.
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Old 11-08-2020, 07:57 PM   #3
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For searching: use google, with "turbobricks" added to the search terms.
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Old 11-08-2020, 09:03 PM   #4
makebrickgovroom
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It's probably advisable to do as much investigation as you can -- check compression/leakdown if you have the time and the resources, as well as doing a lookover of the belts, gaskets, hoses, wiring insulation, etc. ; you'll thank yourself in the future if you can at least identify any other problems the car might have. You never know what might be lurking, especially if the car has been haphazardly modified by previous owners.

Have you tried a known-good MAF? I have a few if you need one.

Have you tested your fuel pressure? How about the fuel pump? Is there any noticeable fuel smell when running?

Have you checked all the grounds for your sensors?

Unfortunately, I don't have any technical specifications for the sensors you listed, but using mikep's suggestion of searching will absolutely get you the information you need. This forum is like a library of some of the greatest RWD Volvo knowledge you can find -- there's at least 20 years of in-depth knowledge on this board, and any question you may have I assure you someone has already asked and someone else has replied with invaluable information. With no prior mechanical experience, I was able to turbocharge and mega squirt my 240 wagon in a couple of months using almost nothing but this board and a handbook.

As a last resort, I know a lot of the Volvo greenbooks have been published online, so you might be able to find what you're looking for there, too.
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Old 11-08-2020, 11:39 PM   #5
jaychen
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Quote:
Originally Posted by Lankku View Post
Because the current chip is unknown, I might start with a chip which is made for that combo. But it wont' hurt to do some measuring first. What is the AFR while cruising and under boost?

With 2.4 you have diagnostics if the wiring has been swapped/modified accordingly. If not, then you can add it.
The wiring is definitely not there to perform diagnostics. Adding it would be a great way to speed up diagnosing problems that are going to occur. I will search for this information.

Quote:
Originally Posted by mikep View Post
For searching: use google, with "turbobricks" added to the search terms.
I did try this, specifically site:turbobricks.com insert search terms

Quote:
Originally Posted by makebrickgovroom View Post
It's probably advisable to do as much investigation as you can -- check compression/leakdown if you have the time and the resources, as well as doing a lookover of the belts, gaskets, hoses, wiring insulation, etc. ; you'll thank yourself in the future if you can at least identify any other problems the car might have. You never know what might be lurking, especially if the car has been haphazardly modified by previous owners.

Have you tried a known-good MAF? I have a few if you need one.

Have you tested your fuel pressure? How about the fuel pump? Is there any noticeable fuel smell when running?

Have you checked all the grounds for your sensors?

Unfortunately, I don't have any technical specifications for the sensors you listed, but using mikep's suggestion of searching will absolutely get you the information you need. This forum is like a library of some of the greatest RWD Volvo knowledge you can find -- there's at least 20 years of in-depth knowledge on this board, and any question you may have I assure you someone has already asked and someone else has replied with invaluable information. With no prior mechanical experience, I was able to turbocharge and mega squirt my 240 wagon in a couple of months using almost nothing but this board and a handbook.

As a last resort, I know a lot of the Volvo greenbooks have been published online, so you might be able to find what you're looking for there, too.
I have not got a spare 960 MAF, as they're hard to find in Brisbane, Australia. I have sent you a PM, perhaps you can post one down if it's not too costly?!

Car smells rich but when purchased it was running around 10.5-11:1 under boost. Now it is extremely lean.

I have a feeling the MAF is my problem, considering disconnecting it affects lambda so much and reconnecting does nothing for it.

Are 960 MAF's safe to clean with MAF cleaner or will it ruin them?

Perhaps my search terms weren't great, I'll try to search for broader topics again.
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