1985 xjs project, engine diagnosis.
#1
1985 xjs project, engine diagnosis.
As I posted in another thread, I've been working on my project xjs.
When I first got it, it started and ran with a little burnt oil at start. The few times after that I could get it to start, it would back fire when I let off the throttle, and definitely was not running on all cylinders.
Fast forward a bit, and it would not start any more. Barely turned over. My battery isn't great, but there's other issues for sure. I checked the oil level and it was way too high. After draining it, I noticed how much gas there was in the oil. I'm guessing this is due to the other issues.
What should I work on first? I have oil and a filter on hand, but can't find a big enough socket to remove the old filter. Close, but no cigar.
When I first got it, it started and ran with a little burnt oil at start. The few times after that I could get it to start, it would back fire when I let off the throttle, and definitely was not running on all cylinders.
Fast forward a bit, and it would not start any more. Barely turned over. My battery isn't great, but there's other issues for sure. I checked the oil level and it was way too high. After draining it, I noticed how much gas there was in the oil. I'm guessing this is due to the other issues.
What should I work on first? I have oil and a filter on hand, but can't find a big enough socket to remove the old filter. Close, but no cigar.
#2
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,856
Received 10,914 Likes
on
7,171 Posts
Gasoline contaminated oil does no harm sitting in the sump but can cause a world of hurt if you run the engine, obviously.
First find out why there is so much gas in the oil and repair that issue....then refill the oil and replace the filter.
One of many possible culprits is injectors staying open due to wires shorted-to-ground. The injector wires often crack after years of being baked by engine heat
Cheers
DD
First find out why there is so much gas in the oil and repair that issue....then refill the oil and replace the filter.
One of many possible culprits is injectors staying open due to wires shorted-to-ground. The injector wires often crack after years of being baked by engine heat
Cheers
DD
#3
Gasoline contaminated oil does no harm sitting in the sump but can cause a world of hurt if you run the engine, obviously.
First find out why there is so much gas in the oil and repair that issue....then refill the oil and replace the filter.
One of many possible culprits is injectors staying open due to wires shorted-to-ground. The injector wires often crack after years of being baked by engine heat
Cheers
DD
First find out why there is so much gas in the oil and repair that issue....then refill the oil and replace the filter.
One of many possible culprits is injectors staying open due to wires shorted-to-ground. The injector wires often crack after years of being baked by engine heat
Cheers
DD
#4
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 24,856
Received 10,914 Likes
on
7,171 Posts
#5
#6
A lot of people have done it and there is a lot of info available doing Google searches.
#7
Trending Topics
#8
If it was backfiring when you let off the throttle and sounded like it was skipping, then it was dumping unburnt fuel into the exhaust. Bad plugs could be a culprit, but so could a stuck injector dumping too much fuel. That could also be why you have gas in the oil as it floods the cylinder and eventually seeps past the rings.
It sounds like your injector harness needs replacing and they really aren't that difficult to make. I've built several using high temp wire, solder, shrink tubing and a loom covering. However, if your injector isn't getting any signal, it shouldn't be opening. So if it were me, I'd first check the plugs and spark plug wires, then if it still skipped I'd start testing the injectors.
It sounds like your injector harness needs replacing and they really aren't that difficult to make. I've built several using high temp wire, solder, shrink tubing and a loom covering. However, if your injector isn't getting any signal, it shouldn't be opening. So if it were me, I'd first check the plugs and spark plug wires, then if it still skipped I'd start testing the injectors.
#9
#10
Gasoline contaminated oil does no harm sitting in the sump but can cause a world of hurt if you run the engine, obviously.
First find out why there is so much gas in the oil and repair that issue....then refill the oil and replace the filter.
One of many possible culprits is injectors staying open due to wires shorted-to-ground. The injector wires often crack after years of being baked by engine heat
Cheers
DD
First find out why there is so much gas in the oil and repair that issue....then refill the oil and replace the filter.
One of many possible culprits is injectors staying open due to wires shorted-to-ground. The injector wires often crack after years of being baked by engine heat
Cheers
DD
And yes, one V12 started in -20C showed as usual lots of white smoke (condensation) which camouflaged the unburnt fuel from two cylinders with injectors stuck open. By the time the engine was warm and I twigged onto the impending disaster the crank was damaged.
Last edited by Per; 01-06-2012 at 10:57 AM.
#11
Injectors stuck open by gumming or rust (water in fuel usually condensation from fuel tank) is rather too common, particularly with cars sitting still for longish periods. I Take them all out and bench test in an injector test rig. Then the stuck ones are subject to prolonged ultrasound cleaning which usually unstick them. Finally I run a bit of fuel through and wrap tightly in plastic until they are to be used again. Be aware that even injectors of nominally the same cc/min will be different if they are of another design than the original pintle type. Both flow curves and patterns will be different. Bad running in particlular at idle and low rpm will be the result.
And yes, one V12 started in -20C showed as usual lots of white smoke (condensation) which camouflaged the unburnt fuel from two cylinders with injectors stuck open. By the time the engine was warm and I twigged onto the impending disaster the crank was damaged.
And yes, one V12 started in -20C showed as usual lots of white smoke (condensation) which camouflaged the unburnt fuel from two cylinders with injectors stuck open. By the time the engine was warm and I twigged onto the impending disaster the crank was damaged.
I'll have to look into cleaning the injectors. My instructor suggested that the valve guides might be shot as well as an injector issues, the slight blue smoke at start indicating the valve seal problem.
I'm going to look at patching up the efi harness as best I can, but my school doesn't have the facilities to test injectors. This is going to sound dumb I'm sure, but can I give the injectors a surface clean with brake cleaner?
#13
Hi Pif,
My son and I found a neat little vid on youtube about how to clean injectors.
The hard part for us was getting the fuel rail put back together pressing all the short hoses back into place.
The cleaning process went well and you'll know right away if an injector is not working. You'll want to purchase all new orings etc, also you should index the injectors so they go back into their respective ports. No really a big deal, but I have been told that unless you can actually test their flow rate don't mix em up.
Our 89 xjs sat for 5 years before we got it. So we cleaned the fuel out and cleaned everything. Now she runs very well with just a few issues regarding tuning and that sort of thing. We are currently tackling the read inboard brakes.
Good luck
Peace
Neil
My son and I found a neat little vid on youtube about how to clean injectors.
The hard part for us was getting the fuel rail put back together pressing all the short hoses back into place.
The cleaning process went well and you'll know right away if an injector is not working. You'll want to purchase all new orings etc, also you should index the injectors so they go back into their respective ports. No really a big deal, but I have been told that unless you can actually test their flow rate don't mix em up.
Our 89 xjs sat for 5 years before we got it. So we cleaned the fuel out and cleaned everything. Now she runs very well with just a few issues regarding tuning and that sort of thing. We are currently tackling the read inboard brakes.
Good luck
Peace
Neil
#15
#16
That's a scary thought. How was the crank damaged? Wear on the lobes?
I'll have to look into cleaning the injectors. My instructor suggested that the valve guides might be shot as well as an injector issues, the slight blue smoke at start indicating the valve seal problem.
I'm going to look at patching up the efi harness as best I can, but my school doesn't have the facilities to test injectors. This is going to sound dumb I'm sure, but can I give the injectors a surface clean with brake cleaner?
I'll have to look into cleaning the injectors. My instructor suggested that the valve guides might be shot as well as an injector issues, the slight blue smoke at start indicating the valve seal problem.
I'm going to look at patching up the efi harness as best I can, but my school doesn't have the facilities to test injectors. This is going to sound dumb I'm sure, but can I give the injectors a surface clean with brake cleaner?
Injector creaning: The trick is to loosen up the pintle and flush out the rubbish. The problem is that the tolerances these things are built to are so close penetrants are not enough. At least that has never worked for me.
Last edited by Per; 01-27-2012 at 01:06 PM.
Thread
Thread Starter
Forum
Replies
Last Post
FS[Western US]: XJS Wiper Motor Upgrade- 76-88 - Electrolux Style
XJsc-guy
PRIVATE For Sale / Trade or Buy Classifieds
0
09-02-2015 11:43 AM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)