Hi Friends,

I haven't posted in a while and I hope everyone is well. I just bought a 'new' 1989 volvo 740 turbo for $300. It had sat on a farm for 6 years with a broken timing belt !

This is my third 740 so I thought I'd take it on as a project. At the very least the car has a good body, rims, and tires (great parts for other two volvos) and came with snow chains - but after hand turning the engine and evaluating it's condition, I think I can get her running

Here is what I've done so far:
-retimed and replaced timing belt. The engine turns over by hand. Nothing seized.
-replace oil seals.
-replaced all accessory belts
-replaced all rotted vacuum line.
-replaced dizzy, plugs, and wires.
-replaced battery.
-siphoned fuel, replaced fuel filter.
-basically did a complete tuneup.

I tried to start it for the first time yesterday. Needless to say, it won't start and won't crank. I definitely have 2 problems but they are not mutually exclusive, 1) the fuel pump is not running when the key is in the 'on' position, and 2) the car won't crank.

The car not cranking is what I really want to focus on:

-With the car in the 'on' position, all lights and accessories on the dash and on the exterior work. The battery is fully charged, and all the batter connectors are clean.
- I tried playing around with putting the car in park - drive - neutral in case it was the parking safety switch. It didn't seem to help.
- I can jump the starter directly from the battery and the engine cranks! This leads me to believe that the starter and selenoid are OK.

I think that something between the ignition and starter is broke. I couldn't find a fuse or relay for the starter. Any help with trouble shooting and diagnosis would be greatly appreciated!

Many thanks!

 

pink wire from pin 50 (start) of ignition switch goes down to the transmission lockout switch buried under the shift lever (on in P or N, off in all other gears), then a blue-green wire on to the solenoid pin 50. no fuses in that circuit. there's also a single wire blade connector under the hood thats on a pink wire, I believe its near the left fender well. jumpering this blade to power should start the car... IF the interlock switch is working. which I'm betting its not.

the interlock switch is fairly inaccessible, but it goes through a 4 pin (2x2) connector on the left side fo the transmission. a manual transmission car has a jumper plugged into this that connects pin 3 and 4, since said manual cars don't have transmission starter interlocks.

 

Hi Pierce,

Many thanks on the prompt response! When I get home from work, I will try to jump the pink wire/connector under the hood and then do some research on the interlock switch.

Seems like there are not too many components to troubleshoot between the ignition and the starter solenoid. Hopefully those said components are not too much of a PITA to access lol.

I'll let everyone know what I find...

Thanks again,
Dan

 

Per Pierce's suggestion,

I found the 2-wire harness with the pink wire on the front left side of the engine bay. (Note: The harness also had a yellow/red wire in the second slot. Everything I've researched seems to say that the pink wire should be by itself in the two-wire harness but it was not on my car).

Since I was unsure if I had the right harness because of the second wire, I checked with my multimeter that voltage was flowing only when the key was turned to the start position. It did, so I took some thermostat wire and jumped from the pink wire to the starter solenoid. It now cranks right up Guess the neutral safety switch is bad. I'll leave it jumped until after I get the car running.

It's getting late but tomorrow I'm going to check for spark at the plugs. Hopefully I do have spark and that would only leave trouble shooting the fuel system and keeping my fingers crossed that everything is in time!

For the fuel system, I anticipate that I will have to do a complete overhaul. It had old gas sitting in the tank and lines for over 6 year and it's a complete mess. I may have to drop the tank and clean it, replace the fuel pumps (with a single high pressure in-tank pump), and replace the fuel lines. Hopefully I won't have to do all that but we will see.

Thanks again!

Here is an exterior pic from when I first got the car. The engine picture I took last week after I finished most of the work. She's looking better now than in the pictures....

 

hmmm, I dont think the 740/940 turbo was ever built a single fuel pump, and the single pump 740/940's (either Regina/Rex, or the last year Bosch in 1995 had lower fuel volume pumps.

its possible you could adapt a 850 T5 fuel pump, as they have similar thirst under full throttle (I have seen < 8 MPG on short sprints across town in my old 850T wagon, hah!)

 

Hi Pierce,

Haha, I believe you are correct! What I was thinking of doing is a little unconventional (though i have read it has been done a few times before).

I'm not sure if I can post links from other sites but if one googles '255 liter fuel pump replacement turbobricks', there have been a few people that have eliminated the main fuel pump and then replaced the in-tank low pressure pump with an Airtex E2366 high pressure pump. This seems like a cheaper, easier, and higher performance alternative than replacing both pumps, especially since I'm considering gutting the fuel system all the way to the fuel rail.

Seems like it has worked for others. Thoughts?

I will post pictures and do a write up if I think that I will need to replace the pumps (in which case I will try the 255l pump mod) and I find that it works lol.

I'll keep you guys posted!

Peace

 

if you're fabricating your own fuel lines, just remember, the main line from the pump to the fuel manifold and regulator is under about 45PSI of pressure at all times when the pump is operating.... ya gotta use pressure rated EFI hose, and not plain fuel hose. volvo uses a metal fuel line thats designed to bend without cracking in a crash.