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- - Help needed (https://www.volvoforums.org.uk/showthread.php?t=281872)

Quote:

Originally Posted by TonyS9 (Post 2404297)

It is firing and supplying fuel, but you have not enough air or fuel.

Fuel pressure reg is a likely cause but pull the vac pipe off and check for fuel leakage or change in engine note.

Check for air leaks, throttle body gummed up (clean with intake cleaner).

Quote:

Originally Posted by Laird Scooby (Post 2404223)

While i remember it, pulling the vacuum hose off the FPR at idle and the engine speed increasing is a sure sign it's running too lean - almost certainly an air leak.

Like i said originally, check the hose between the MAF and throttle body for splits and security - also check the hose between the EICV and the inlet manifold for the same.

Quote:

Originally Posted by Gareth2510 (Post 2403942)

Hello my 940 has a problem its a 1997 2.3 lpt. If i start it it dies give it some gas it will stay alive take my foot off the gas and the rpm drops to the point of stalling & engine light comes on. If it doesnt stall it will hover around 450-500 rpm. I have tried fitting a new coil, crank sensor, and ignition module still has the same problem. I have tried a different fpr rpm increases if i pull the hose. Has a new distributor & arm new fuel pump etc. I have cleaned the eart leads on the manifold resoldered points in radio suppression relay & fuel pump relay ( clicks when priming ) rsr clicks after a few mins of ignition being cut. Now one thing i do notice is the longer of the two injection resistors gets red hot cant even touch it hot. Any ideas as to what the problem could be would be a great help.

Just in case you missed it Tony - previous references to the FPR and what it's doing on his engine, all points to an air leak somewhere on the inlet side i reckon?

I wonder about the inlet manifold gasket, i think the pink visible ones can leak but thater, green, not easily seen don't?

I sprayed some carb cleaner around all the injectors & manifold no change in rpm. I have sprayed soapy water on air hoses & joints no bubbles or leaks visually checked hoses for splits or oil damaged parts that might collaps. Just done a draw test to see if the voltage regulator was acting up but all is ok.

Quote:

Originally Posted by Gareth2510 (Post 2404365)

Sadly none of those tests are conclusive. You need something like WD40 or better still, ether (aka EazyStart) to spray round the manifold etc with the engine running and also the hose/pipework between the throttle body and the MAF. Also make sure the electrical connector is plugged in properly on the MAF.

As for spraying soapy water on the various air/vacuum hoses, again it won't work. There's no air pressure there, especially on the vacuum hoses so you won't see any bubbles.

What are you calling a draw test? I'm guessing you put a voltmeter across the battery terminals with the engine running? If so, what did it read?

agree not a very good way to test i heard gas was also good so i tried that as well again no change. Draw test was 13.4 idle 14 on load 12v engine off.

anyone disconnected the injectors in turn yet?

Or are we assuming they are all operating ok?

Engine is running lean apparently. No vacuum leaks apparently. No idle control fault apparently. Hmmmm - what else is in the mix, easy to get to and takes 30 seconds to isolate?

:angel_smile:

Quote:

Originally Posted by Rversteeg (Post 2404183)

It is actually item 7/46, a plain resistor, nothing else to it and it IS the one in the picture.

About the ICV, just ground pin 1 of the TPS and start the engine. Just to be sure...

Thats interesting. They changed the circuit significantly between '95 and '97.

Bloody glad we didn't have that crap over here!

Quote:

Originally Posted by aardvarkash10 (Post 2404426)

Pulled the injector plugs 1 by 1 yesterday. No change in how it ran. Got a 223 code for the idle control valve. Will be testing another valve today.

Quote:

Originally Posted by aardvarkash10 (Post 2404542)

Thats interesting. They changed the circuit significantly between '95 and '97.

Bloody glad we didn't have that crap over here!

They didn't Ash - have a look at this thread :

https://www.volvoforums.org.uk/showthread.php?t=281270

That's on a 1995 car. I had a dim-dip resistor on my 1988 740s (not looked for it on my current 760) yet the Haynes Book of Fantasy shows a similar circuit to the ones linked to above.

For some reason Volvo show this similar diagram in all their dim-dip circuits but all of them that i've come across have had that resistor.

One of the quirks of UK models! ;) :D

I had idle issues, where the idle was uneven, which was massively improved by simply removing the ICV, blasting it with carb cleaner and refitting.

A more recent idle issue, where the idle had dropped, was cured by adding a petrol system cleaner additive.

This has various diagnostics and suggestions for idle problems;

https://www.volvoclub.org.uk/faq/Eng...#Idle_Problems

Quote:

Originally Posted by Laird Scooby (Post 2404361)

I saw the reference to the FPR, just thought it may have been forgotten about in the resistor digression lol

I did have a leak caused by the inlet gasket. I hadn't tightened up the nuts evenly enough and the manifold was kinda on at an angle leaving the disti end end a bit loose and the gasket uncompressed. It didn't leak, but eventually the gasket got brittle and a bit cracked and broke off. Didn't cause idle problems though, as was small enough to be compensated for by the idle valve.

Make sure the gasket compression is even at either ends of the manifold.