'91 240 issues
 

Hello all,

I'm having a problem with my 1991 Volvo 240.
During normal driving it seems to not be getting enough fuel at higher speeds. Right now the car does not have a lot of power and will not go faster than 55mph. If I clamp the fuel return line it will easily hit 80mph but then (predictably) is getting to much fuel in the lower speeds and idle. I am at a total loss as I have already cleaned out the fuel lines, changed the fuel filter, changed the fuel pump and changed out the fuel pressure regulator.

Any ideas?
Graham

I forgot to mention, this is a B230F engine with a Bosch fuel injection system, the ECU and in tank pump have both been swapped with known working ones.

I presume the check engine/lambda light is on? If so, there are codes to be read-

https://www.volvoclub.org.uk/faq/EngineOBDCodes.html

Read the above guide and see which fault codes the system has stored, then reply on here.

My guess is the lambda sensor, but check the codes before buying parts.

Cheers

Thank you for the reply,

The lambda (o2) sensor did go bad and was replaced about a month ago, I'm not getting any codes (or CELs) since replacing it besides the occasional 2-3-1 - Lambda control - too lean or too rich at part load.

Have you checked, cleaned and/or replaced the fuses? It's important -- I believe that the fuel pump is fuse number 6.

Yes I have checked the fuses and the relay, both pumps are turning on.

This is a tough one. It's possible that your new O2 sensor has failed, especially if this never happened before replacing it. Given that you've been swapping in parts, I assume you have easy access to spares. I'd be tempted to switch out the ICU, as you already switched out the ECU.

I have an 84' that I have been pulling parts off of just to see if it works. Does anyone know if the ICUs are compatible between the two years?

I think... but only think, that the two ICUs were different designs and therefore simply not interchangeable

My '91 B230F has an ICU which goes thru' 90 degrees (the earlier one I believe is in line) and is Bosch p/n 0280140516 if that helps

Good luck

Wait a sec - has this problem appeared since you changed the lambda sensor?

It's entirely possible it has failed again - I had a new one fail within a few weeks once, which was obvious when I removed it as the interior porcelain insulator was broken and rattled when I shook it.

If you can get under the car and remove it to have a look then I'd suggest that as a very first step - should be easy to unscrew if it was replaced recently.

Cheers

If you disconnect the MAF does it get even worse or stay the same?