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Old 07-19-2021, 12:34 PM   #1
mr_headshok
Newbie
 
Join Date: Jul 2010
Location: Belgium
Default LH2.4 issues with a stock B234F

Hi guys,

I've been around carb'd Volvos since I got my driving license almost 20 years ago, but I still need to learn alot about fuel injected cars. So that's why I'm here

I have a question for the LH2.4 experts out there.
I'm running a stock B234F in my Amazon wich has developed a problem with the fuel injection.

The symptoms are:

Sluggish power from standstill with open throttle.
Slight pops and bangs from the exhaust on the overrun.
Higher idle rpm when hot
Slow throttle response at lower rpm
Flooring it at lower speeds result in severe hesitation and (what I think) backfiring in the exhaust. Although I heard it once from the intake.

Things I have done already:

AMM is new and has been swapped over without any result.
TPS is new and has been adjusted accordingly
Fuel pressure regulator swapped out without result
O2 sensor voltage drops rapidly to absolute zero when applying throttle, but remains stable when at idle rpm. And it doesn't go over 1V (read with digital voltmeter)
At higher engine rpm it still goes as it used to, but it seems down on power when accelerating.
Fuel mileage does not seem affected.
Spark plugs are out and show grey/black deposits. they will be cleaned and regapped and put back in.
Distributor cap and rotor have around 5k miles on them. (will be checked later this week)

My guess is the knock sensor or engine temp sensor for the ECU, but other suggestions are more than welcome.

As fas as fault code readout goes there is an issue.
I'm running a Lh2.4 loom from a 240 because that was easier to adapt for my stand alone purpose. The diagnostics box is still there, but doesn't seem to do anything. (or I could be using it wrong)

Thanks in advance
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