1981 242 GLT Turbo K-Jet/CIS

I suspect the main pump is not delivering full volume. Pump has over 100K on it. I get to full boost and the engine strains/starves. Cat is new, ignition checks out correctly, fuel pressure is spot on. Used the bypass valve on the fuel pressure gauge to isolate the control pressure/warm up regulator, which works well, and peformance is worse which leads me to the conclusion that the WUR/CPR is not the issue and the volume to support running under full system pressure is not there.

In tank pump draws 1.5 amps as normal. Checked the amp draw for the main pump and it is 7.5 amps. Spec says 9.5 (max) so I'm thinking 7.5 is too low and the pump is not working well enough to draw the amps at 12 volts to produce the volume.

What say the specialists? Many thanks... (I have not measured the output in a metering receptical as I wanted to get the amp draw opinion). I think this is the issue.

 

You running stock boost levels? I think the amp values for the inline pump are fine frankly. You could always swap in a Bosch 044 and throw the Pierburg pump away...although KJet inline pumps are not too shabby. I presume you've already exhausted the usual suspects such as filters...

 

Yes, filter is new. Went through the entire system. The only thing I think it can be is fuel delivery under full boost @ 11.5 psi. Ran fine until a few days ago. The clue is bypassing the WUR/CPR with the bypass valve on the fuel pressure gauge and it ran worse under boost. That requires all the pump can deliver. Ignition coil measures correctly, impulse measure correctly, no ignition faults anywhere. Back off the throttle a tad and the problem disappears.

I can only think of the pump and 7.5 amps is a bit low I thought. It's the only thing left. Thanks for the reply. I appreciate it.

 

Well, that's max p.s.i. for KJet for sure. Factory spec is 7 or 8. If the car was here at the shop, we'd put a fuel pressure gauge on it, run the hose and gauge out and stick it under a wiper where you can see it and go drive it under those conditions where it seems to fail. If the fuel pressure dumps, then I'd either swap in a new and improved pump...at least a Walpbro GSL 392 or much better, a Bosch 044. Swapping in an intank lift pump from a later LH car will boost the gasoline getting to the main pump; KJet tank pumps are anemic. You might also check the actual voltage getting to the main pump. Many people pull a dedicated circuit with relay from the battery/alternator to get 13 or 13.5 volts at the pump which will obviously improve pump performance.

 

I installed the intercooler kit from a later model with all the supporting bits so it runs at 11.5 psi, which is stock for the intercooler model, with no problems. I have the 128 WUR/CPR in it and the car runs exceptionally well. This issue just started. Come to think about it, it happened in one hell of a rain storm. I'll measure the voltage at the pump. I may need to upgrade that wiring. The relay doesn't get hot and I corrected an issue there last year which was making it get hot and fail. The voltage or wiring just may be the culprit. The pumps were working just fine. The in tank pump is the upgraded one. I forgot which Bosch is the main one. I check that out when I check the wiring.

Voltage is being checked now. Thanks for the tip. I'll post back up. BTW, Bosch 044? What model did that come out of so if I do need a pump, I can score that one?

I've had this car since new in 1981 - the first turbo Volvo produced. I chirped the tires right off the showroom floor when I took it out. I refurbished it around the original engine and driveline although I did have new bearings in the trans, OD and diff installed as well as new brakes and such. Runs like the wind - nice and smooth - at 252K with zero engine work done. It was built in April so I'm throwing it a party.

Thanks again for the voltage tip. I plumb forgot about that. Forest and tree thing, I guess.

 

I have 13.5 volts to the main pump and 12.5 to the internal pump. The main draws 7 amps but the one in the tank is drawing 1.15 amps. Apparently it is the older model. I'm going to pull it out, check the sock and upgrade it. It worked fine and doesn't make any noises but it is probably due.

 

I'm not finding any problems. Now this is making me think maybe its the impulse sending coil. I measures correctly though. Frustrating this... when I get into it, it feels like its starving for fuel or maybe spark strength... Problem is replacing the pumps is expensive only to find out its not them. I'll see if I can stretch the fuel pressure hose up to the cowl so I can watch it. That outta tell me what's what.

 

Well, interestingly enough, I put the fuel pressure gauge on the cowl where I could drive and see it - a first for me. I saw a 1 psi drop at best when the engine bogged down. I am wondering if the pressure is fine but the volume isn't? It feels like the old days of points when they were too close together. Bogging down. or when you don't get enough fuel. They are so close together in how they feel. Back to square one it appears...

 

Ok, I found the problem. The relay connector had loose connections. The plastic housing was also deformed. When the main pump failed 15 years ago, it drew more current, generating more heat which deformed the connector. I got rid of the plastic connector, re-crimped and tightened the connectors and measured right at the relay - before and after- all good.

Took the car out and nailed it - good to go. In fact, the fuel delivery was superb. The car even ran stronger than before. I was giving all it could. Another benefit - the intermittent hot start problem I had is gone which has been my nemesis for years.

All systems measure correctly. Moral: Check those connections!!!

 

I notice that I have 13.5 volts going to the relay on #30 and 12.7 on the pump side #87 when cold. As the relay gets hot, voltage sags a bit below 12 volts. I noticed that voltage varies as the relays get older too. I tried a few junk yard spares I have and measured this.

Given that the pump relay is handling the current draw of both pumps and they are notorious for failing, I think I'm going to plumb in a more robust relay. I'll take the pumps off #87 of this relay and put them on a Volvo headlight relay I just happen to have. I'll wire #87 from the fuel pump relay to the new relay to trigger it.

That should take care of this.

 

While upping the voltage to the pumps helped out tremendously, I pulled the plugs and discovered they were at .035. I reset them to .028 and that completely eliminated the bogging down. Now that the pumps have 12.5 volts and the plugs are set correctly, the car runs exceedingly better than ever.

 

I love it when a plan comes together! Good news!!

 

Thanks, I appreciate it. Its a 30 year old car. Now I have a hunt-n-peck on idle. It idles swell then decides to surge intermittently. I remember in the back of my head what causes this but can't pull it to the front of my head. I think it could be the coolant sensor which tells the idle CPU where to set the idle motor but it feels like it's going to die then surges to try to settle. It is electrical I'm sure.

I'll mess with it in the morning. If you have a suggestion to jog my memory, I'd sure like to hear it.

 

Problem solved. I re-seated the connector to the ECU which controls the coil. It was a bit loose due to all the work under the hood in tracking down the performance issue. I hope these tips will help others...

 

Decided to peek at the injector seals. Replaced them about 20K ago but they looked like they could use a change. Sure makes a difference I gotta say. I'm going to replace them when I replace the spark plugs from now on. Cheap and easy to do anyway.

The old boy is almost ready for his 30th birthday party. Tomorrow the air conditioning gets converted to a rotary compressor that is more efficient with less drag on the engine. That's its 30th birthday present.

Thanks for listening!