Hi Guys,
I am hoping you can help me out. I am restoring a 1987 Volvo 740 with 129K with my grandson for his first car. It is in great shape, runs great, but has one issue. On the first start up of the day, cranks over fine, runs about 10sec and dies. Does the same the 2nd time. On the 3rd start, it almost stalls, then runs fine with an idel of about 1100 rpm for about a minute, then slows to 750rpm. Drive great, good acceleration, no issues at all.
I checked the fuel line pressure it is about 40psi, the fuel pressure regulator was changed because it was leaking, all new seals on the injectors, all new vacuum lines, cleaned the throttle body, new gasket. New coolant temp sensor, and checked for vacuum leaks using brake clean. Also put in a new Bosch fuel line check valve by the main pump. fuel filter was also changed

ANY help would be great appreciated. Fuel is fresh 89 octane

Thanks
Lewis

 

Goldenblock here!!! Lets try checking/ cleaning your Idle air control valve. In addition check condition of your air filter.

Goldenblock 2 million miles and still going...

 

If after it starts it idles @1100 then down to 750 - That sounds like your idle motor/air valve/IAC or whatever you want to call it - is working. But I would certainly clean and verify that component is good and the throttle plate is clean, throttle switch adjusted and plate is adjusted so the engine will idle with the idle motor air flow blocked off.

If it stalls even while trying to add more air with the gas pedal when first started cold -

You might have a bad air temp sensor in the Air Mass meter - I have replaced many (years ago) that did not enrichen (sp) the mixture enough when cold to prevent stalling. Not sure where/what the temp is where you are - but I would see this problem worse in colder weather. I'm in Georgia so cold is a relative term here. I wouldn't purchase an air mass meter on a guess - I always had my techs substitute a known good (or new) meter first. That may be harder nowadays though -

Some customers chose to just live with the early morning stall although now i see a meter for that car is 1/4 the price they used to be -

If it's a lean mixture stall it's possible the injectors are partially clogged, being 20+ years old - I'm not suggesting replacing them, maybe using Techron gas additive for a few tanks of gas and see if that helps.

 

does that version have the 5th 'cold start' injector? those are only turned on for a few seconds during a cold start, and if its not working, I bet you'd get symptoms like you're seeing. later years got rid of it instead the newer ECU would just squirt more fuel with the main 4 injectors and do the same thing.

 

Hi Guys,
OK found the problem, it is the idle air control. My friend gave me his to try and runs like a dream. Problem now is I can't find one. Any help would be GREATLY appreciated.

Lewis

 

here's the IAC for a Bosch LH2.4 system, which would be an 89+ 240/740/940 thats not Regina
https://www.fcpeuro.com/products/vol...140516#fitment

not finding the LH 2.2 or regina IAC, dunno what the differences are.

 

is this the IAC for yours ?

 

As a free work around - Have you tried adjusting your base idle up so the car will run with the air flow to the Idle valve blocked off? That way you won't be depending on the idle valve to raise the idle speed as much when cold. Clean the throttle plate and set the idle speed (with the throttle plate set screw) and properly set the switch so the car will idle @750 when hot with air flow blocked off the the valve. Then see if it will idle and not stall when first started - The idle speed will be low because the engine is cold - but you may make the car driveable.

 

Hi Guys,
We I found a NOS Bosch IAC, coming here on Friday. Hopefully the car will be back on the road again. My grandson can't wait!!

Have a Happy Thanksgiving

Lewis

 

Well thankyou very much. My very first post mentioned that glad it helped you!!