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1982 Volvo 244 Kjet Turbo Hot Start Issue

Murploid1

Murploid1

Member
Joined
Apr 6, 2017
Location
Houston, Texas
Hello,

I am having an issue with my B21FT KJet not starting when hot, if the car has been running and left for 30 mins it is fine, any longer will not start unless its cranked for a long time - starts easily when cold.

The car has an issue with the main fuel pump, started making grinding noises and starving the car of fuel after around 30 mins of driving, also the relay doesn't appear to be working - doesn't click and very warm.

Some positives:
  • In tank pump is fine
Fuel injectors and seals have been replaced


I have both a main fuel pump and a relay on order and will replace when they arrive next week. My question is should I also replace the fuel accumulator? Presumably there is one?

Not sure the relay and the fuel pump will resolve the hot start issues? The car must be losing fuel pressure?

Any help appreciated.

Thanks!
 
Connect a test light to the wires at the cold start injector. When cold, the thermal timer will activate the injector continuously while the starter is cranking for a period of a few seconds. When warm, the impulse relay will activate the injector approx. 1.5 seconds after the starter is cranked for a period of .2 seconds followed by a pause of .3 seconds etc.
 
K-Jet is FANTASTIC

n front of the main pump there is a check valve, when they go bad they will slowly leak back pressurized fuel making it hard to start , ie when line pressure drops it takes a while to build back up while you still have a defective check valve. When replacing this 19 dollar thing be carefull to NOT damage the power terminals , also dont re use the same copper washers , UNLESS you un_kneel them -> heat let cool, Then ofcourse a a little ruba dub dub on some 220 sand paper will do quite nice ,a old trick we did in nam.............
 
Wouldn't mind some feedback on pump squeal if anybody has any thoughts..

I had the main pump replaced , I was convinced this would resolve the hot start issue as this pump (I thought) was making a loud groaning sound after around 20 mins of driving.

Seems that the sound is still around when things heat up as is the hot start issue. Car runs fine once started, never dies.

I guess its in the in tank pump? UGH!

I had had the pressure tested only a couple of months ago and it was fine.

Could the in tank pump be causing these hot start issues?
 
I'm having the exact same problem with my 82 242 turbo. I bought the car after it sat for years so I replaced both fuel pumps and check valve. I replaced the accumulator last week with no change. The accumulator was leaking at the back screw (when I removed it and started car). That means the diaphragm was broken. I thought for sure the new accumulator would solve the problem but no.

I have a cold start injector too. I tested the current to it last weekend. It gets about 10 volts constant when I start the car hot or cold.

When I can't start the car hot (warm actually) a good shot of starting fluid does the trick.

i replaced tho o rings on the injectors. I was thinking of replacing the injectors next.

Please keep posting your attempts so I can see what works and what doesn't for you.
 
Another hot starting issue is caused by a fuel mixture setup to the lean side of the adjustment. After a fresh oil change and air filter. If all is well you can try a slight adjustment say about 2 maybe 3 degrees of dwell decrease at fully warmed up idle. You use a dwell meter on the red lambda cycle wire on the left inner fender to monitor the adjustment. Be sure there are no vacuum leaks or other problems that can lean out the idle mixture.
 
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I'm going to replace the in tank pump and see if this resolves the issue. I presume that the main pump (brand new Bosch) is squealing because it's not being supplied with enough fuel. Only happens when warm.

Also, can other owners advise if they can hear the fuel pump priming whilst the ignition is on? I hear nothing. I have tried jumping it (bypassing) relay and it makes no difference. But the intank pimp must be working when it's cold as it starts. When it's warm it requires cranking and cranking, eventually the main pump pulls fuel from the tank and it fires - takes about 30 seconds of trying and playing with the throttle.

My fuel setup is lean but I do not believe this is the issue. If I leave the car for 30 mins after starting it fires right up - presumably there is fuel in the lines.

Also note this issue arises when the main pump is squealing for mercy...
 
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Ok thus far I have replaced the following:
- both fuel pumps
- both fuel filters
- fuel pressure regulator
- fuel accumulator
- injectors
- spark plugs
- distributer rotor
- distrubuter cap

Thing still does not want to start when warm. Will start after leaving for 30 mins, leave it for an hour - I have to repeatedly crank and work it to start. So I am wondering of the warm up regulator needs attention.

Where is this located, easy to remove? Looks like quite a simple device from what I have read. Will check the voltage going to the unit and clean if necessary.

At this rate the starter motor is going to give up soon..
 
You have to get a kjet fuel pressure setup and know what the warmup regulator aka the control pressure regulator is doing. It will also let you test system pressure and rest pressure which are all very important with kjet. It is located behind the distributor under the intake manifold. there are two fuel lines to it and an electrical connector.

You also need to get a dwell meter on there and find out what the lambda controller is doing. Then you will know if you need to adjust the mixture and/or replace the o2 sensor.
 
With all the parts replaced on that list. If the control pressure regulator is good and there still is a hot start issue. Then I'd try just slightly tweaking the fuel mixture just a bit richer. But I would be sure all other related parts like the control pressure with a hot engine is correct.

For example my turbo didn't like hot starts. It needed a fuel accumulator. That made it work well but it still needed a little help. I started adjusting the fuel mixture dwell to 39-40 degrees with a hot engine. Stock is 41-44. That seems to have cured it. I chalked it up to the cam made the engine like a bit more fuel for hot starts and it's been happy ever since.
 
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