Shark will not run over 2500rpm - Update
05-31-2005, 01:02 AM
#1
Burning Brakes
Thread Starter
Shark will not run over 2500rpm - Update
Well...not a good update, in fact I'm moving backwards here.
A few weeks back my shark began to run poorly and would all but sputter at 2500 rpm and up. I had initially thought fuel injection issues were the problem so I completely diagnosed the fuel system - everything is in spec.!
I then moved to ignition - removed the distributer cap, cleaned things up and installed. Started the shark, checked and made a small adjustment to the timing. She ran much better at this point, lack of power at 2500rpm but no sputter and threat of stalling. I must be on to something here...
I decided to order a new coil, .4 and .6 ohm resistors and roter (the plug wires and cap are new as well). I also double checked the green wire, which is new, but I had heard about a potential manufacturing problem - green wire is good.
Installed everything and she ran, but I it literally shounded like she was running on two chlinders. Scratched my head and checked everything with the multimeter, started and- pud-ppud-pppuud-ppud-pud. Not the bwaahahh I'm used to. I'll double check the timing in the morning but other than that I have no clue at this point, anyone out there have any idea - I need some help here. Can a bad ignition box be the issue? What about a bad fuel pump relay?
A few weeks back my shark began to run poorly and would all but sputter at 2500 rpm and up. I had initially thought fuel injection issues were the problem so I completely diagnosed the fuel system - everything is in spec.!
I then moved to ignition - removed the distributer cap, cleaned things up and installed. Started the shark, checked and made a small adjustment to the timing. She ran much better at this point, lack of power at 2500rpm but no sputter and threat of stalling. I must be on to something here...
I decided to order a new coil, .4 and .6 ohm resistors and roter (the plug wires and cap are new as well). I also double checked the green wire, which is new, but I had heard about a potential manufacturing problem - green wire is good.
Installed everything and she ran, but I it literally shounded like she was running on two chlinders. Scratched my head and checked everything with the multimeter, started and- pud-ppud-pppuud-ppud-pud. Not the bwaahahh I'm used to. I'll double check the timing in the morning but other than that I have no clue at this point, anyone out there have any idea - I need some help here. Can a bad ignition box be the issue? What about a bad fuel pump relay?
05-31-2005, 01:37 AM
#2
Scott,
You can check the relay by jumping the 15 and 87 pins on the relay board. Have you done a visual check on the spark to see if you are getting a good, regular spark on multiple wires? Fuel filter, bad internal fuel pump (if installed), corroded fuel pump fuse and bad grounds are all possibles if your problem is fuel related. Do you smell fuel and get a black exhaust when it is pppuuding?
Have you checked to see if the timing belt has jumped some teeth?
Dennis
You can check the relay by jumping the 15 and 87 pins on the relay board. Have you done a visual check on the spark to see if you are getting a good, regular spark on multiple wires? Fuel filter, bad internal fuel pump (if installed), corroded fuel pump fuse and bad grounds are all possibles if your problem is fuel related. Do you smell fuel and get a black exhaust when it is pppuuding?
Have you checked to see if the timing belt has jumped some teeth?
Dennis
05-31-2005, 03:36 AM
#4
Rennlist Member
It's probably the green wire... goes from the distributor to the ignition box. If it looks at all questionable, replace it. If it looks like mine did(below) you're overdue! 
05-31-2005, 04:27 AM
#5
I've had similar problems on my 79.
Make sure your rotor is set in the distrbutor, give it a really good push.
Make sure all of the spark plud threaded ends are on correctly.
Make sure your spark plug leads are positivly on, I had to push really hard when I got new leads to set them into to the wells.
I found I had to bleed my WUR at the inlet after I had cleaned the screen there.
Tripple check all vacuum conections.(in case you bumped something off )
Do you have your vacuum limiter still hooked up?
If so pull the vacuum line plug it, and see if it runs better.
Maybe your aux air valve is sticking open or closed intermittently.
Make sure your rotor is set in the distrbutor, give it a really good push.
Make sure all of the spark plud threaded ends are on correctly.
Make sure your spark plug leads are positivly on, I had to push really hard when I got new leads to set them into to the wells.
I found I had to bleed my WUR at the inlet after I had cleaned the screen there.
Tripple check all vacuum conections.(in case you bumped something off )
Do you have your vacuum limiter still hooked up?
If so pull the vacuum line plug it, and see if it runs better.
Maybe your aux air valve is sticking open or closed intermittently.
05-31-2005, 10:19 AM
#6
Burning Brakes
Thread Starter
Thanks guys for all the replys. A little more info:
- I can smell a little fuel at the exhaust but no black smoke at all.
- Cat is not clogged - I have a gutted cat
- Green wire is new and tested
- Fuel filter and external fuel pump are new. I checked fuel delivery - 1600cc in 30s at fuel dist inlet (tested at fuel distributor), 1100cc at fuel dist return to tank (tested at fitting by passanger cam tower.). System pressure 5.4 bar.
How do I know if the rotor is all the way on - will I feel a "snap" when setaed.
My vacuum line was hooked up to the distributer. What does it mean if I pull it off and she runs better?
- I can smell a little fuel at the exhaust but no black smoke at all.
- Cat is not clogged - I have a gutted cat
- Green wire is new and tested
- Fuel filter and external fuel pump are new. I checked fuel delivery - 1600cc in 30s at fuel dist inlet (tested at fuel distributor), 1100cc at fuel dist return to tank (tested at fitting by passanger cam tower.). System pressure 5.4 bar.
How do I know if the rotor is all the way on - will I feel a "snap" when setaed.
My vacuum line was hooked up to the distributer. What does it mean if I pull it off and she runs better?
05-31-2005, 12:04 PM
#7
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Scott,
You're flying in the dark. You won't get anywhere but poorer by cherry picking parts. If you wish to confirm or eliminate the spark system, you need to look at the spark signals on an oscilloscope. Many shops have special diagnostic rigs and they could tell you in a few minutes if your spark system is shutting down (very unlikely).
As previously recommended, you need to check the system and control pressures on your CIS fuel system. I know you don't want to spend the money on this expensive fix, buy after having much the same problems with my '79, my gut says you have a fuel distribuor problem. Get it checked out.
You're flying in the dark. You won't get anywhere but poorer by cherry picking parts. If you wish to confirm or eliminate the spark system, you need to look at the spark signals on an oscilloscope. Many shops have special diagnostic rigs and they could tell you in a few minutes if your spark system is shutting down (very unlikely).
As previously recommended, you need to check the system and control pressures on your CIS fuel system. I know you don't want to spend the money on this expensive fix, buy after having much the same problems with my '79, my gut says you have a fuel distribuor problem. Get it checked out.
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05-31-2005, 12:17 PM
#8
Burning Brakes
Thread Starter
Rich,
My gut is beginning to tell me fuel distributor too. By the way, all control pressures are in spec.
Went back to work on the shark this morning, my goal was to double check the timing. Removed the distributor cap, positioned crank to TDC and checked cam and rotor position. Cams right on the money, rotor was way off.
Apparently, when I positioned the dist. to remove the green wire, I lifted a bit too high, the gear moved and I did not notice. I aligned rotor put everything back and she fired right up. In fact, she started better cold this morning than in recent memory. What a relief...
The start was promising, but she still does not run well under load. She will rev much better, but under load and at 2500rpm and up the shark surges, misses and has a general lack of power. Very little accceleration once out of first gear.
My gut is beginning to tell me fuel distributor too. By the way, all control pressures are in spec.
Went back to work on the shark this morning, my goal was to double check the timing. Removed the distributor cap, positioned crank to TDC and checked cam and rotor position. Cams right on the money, rotor was way off.
Apparently, when I positioned the dist. to remove the green wire, I lifted a bit too high, the gear moved and I did not notice. I aligned rotor put everything back and she fired right up. In fact, she started better cold this morning than in recent memory. What a relief...
The start was promising, but she still does not run well under load. She will rev much better, but under load and at 2500rpm and up the shark surges, misses and has a general lack of power. Very little accceleration once out of first gear.
05-31-2005, 12:43 PM
#9
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2500rpm
Scott, did you check the small filter inside the incoming fuel fitting into the fuel distributor. This can get clogged and will limit the amount of fuel into the engine.
05-31-2005, 12:49 PM
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OK - so stop looking at the fuel system, and since it basically runs, there is a reasonable chance the ignition is OK too. There is a small screen filter on the inlet side of the fuel distributor - just check that and that might tell you if you need to also replace the rear filter.
I'll say it - most running problems in CIS 928s is because of AIR leaks - air getting into the intake other than through throttlebody, and messing up the delicate balance of air/fuel. Suggest you begin to block off any vacuum lines running from the plenum, then continue looking for air leaks.
'79 Euro +/-
'80 SC +/-
I'll say it - most running problems in CIS 928s is because of AIR leaks - air getting into the intake other than through throttlebody, and messing up the delicate balance of air/fuel. Suggest you begin to block off any vacuum lines running from the plenum, then continue looking for air leaks.
'79 Euro +/-
'80 SC +/-
05-31-2005, 01:27 PM
#11
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Gutted cat, i had someone gut a cat once and i guess they left a chunk in the cat and it came lose and got stuck in the muffler. The car wouldnt run over 3000rpms or so. So that might be something you might want to check also. After that happend to me i no longer belive in gutting cats, better to just remove them.
05-31-2005, 01:38 PM
#12
Burning Brakes
Thread Starter
Definately no chunks of catalyst left inside - no bolckages.
All vacuum lines and seals are new - replaced when the engine was out last year. Fuel filter is new as well. I pulled the fuel inlet at the dist. and had a look. I did not see a screen at the inlet. Is it tucked away inside the inlet?
I've checked for plenum leaks before, but I'll double check.
All vacuum lines and seals are new - replaced when the engine was out last year. Fuel filter is new as well. I pulled the fuel inlet at the dist. and had a look. I did not see a screen at the inlet. Is it tucked away inside the inlet?
I've checked for plenum leaks before, but I'll double check.
05-31-2005, 05:17 PM
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screen is in the inlet fitting, as I recall.
there may also be little screen 'cups' on each of the injector lines at the distributor.
I met a guy who debugs CIS with a propane torch. Not lit of course, just flowing propane. he wanders it around the plenum and air intake areas looking for air leaks, and when the engine sucks in the propane, it revs higher. Not an exact science, and could be dangerous, not something I'd recommend.
Check the vac system for a bad check valve, or block off the plenum vac lines (don't drive the car, there will be no brake booster), then I'd have a look at the plenum boots, throttlebody, decel valve, and all lines/fittings on the airbox, aux air reg.
after 2500 will be difficult to figure out - since engine vacuum is probably less than at idle. Does it idle normal, or have you already adjusted it so that it DOES idle normal now?
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'80 SC +/-
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there may also be little screen 'cups' on each of the injector lines at the distributor.
I met a guy who debugs CIS with a propane torch. Not lit of course, just flowing propane. he wanders it around the plenum and air intake areas looking for air leaks, and when the engine sucks in the propane, it revs higher. Not an exact science, and could be dangerous, not something I'd recommend.
Check the vac system for a bad check valve, or block off the plenum vac lines (don't drive the car, there will be no brake booster), then I'd have a look at the plenum boots, throttlebody, decel valve, and all lines/fittings on the airbox, aux air reg.
after 2500 will be difficult to figure out - since engine vacuum is probably less than at idle. Does it idle normal, or have you already adjusted it so that it DOES idle normal now?
'79 Euro +/-
'80 SC +/-
www.eaglesledge.com
05-31-2005, 07:14 PM
#15
Burning Brakes
Thread Starter
DK,
The shark idles normal and, as of today, starts normal too. Although the engine will judder slightly every now and again at idle. Not completely smooth...
The shark idles normal and, as of today, starts normal too. Although the engine will judder slightly every now and again at idle. Not completely smooth...