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Topic: Shuddering engine...UPDATE July,1 (Read 14864 times) previous topic - next topic

Shuddering engine...UPDATE July,1

Reply #120 –
I'll try to run a compression test on it as soon as I can. Gotta get the gauge and fitting from Autozone when I have the time.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Shuddering engine...UPDATE July,1

Reply #121 –
Vinnie,

There are screens in the injector and that could be plugged.  I wonder if the injector was dribbling rather than spraying if it could easily puddle on a slow acceleration or deceleration and cause a backfire???  Maybe Tom and answer that one.  Another way to check is just swap the injectors around on 7&8 and see if if follows.  It would eliminate the injector if it did not and point to wiring or the salt a pepper shakers if your car has them like my Coupe does.

This is the place I sent my 24# injectors to and they cleaned them up really well and the car actually idled much better.

http://doctorinjector.net/

Darren

83 351W TKO'd T-Bird on the bottle


93 331 Mustang Coupe - 368 rwhp

Shuddering engine...UPDATE July,1

Reply #122 –
I have 4 kits coming for the injectors (4 sets for 4 V-8 engines). It has screens and all. I will swap the injectors around and see what happens. Stay tuned.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Shuddering engine...UPDATE July,1

Reply #123 –
Swap injector 7 with 8 and rerun cyl balance test... See if it follows the injector..Also check the injector harness on 8 for the pulse
[SIGPIC][/SIGPIC]

Shuddering engine...UPDATE July,1

Reply #124 –
I'll swap the two injectors some time this weekend. No time for the next two days.  !!!!!

I'll do that then run the balance test again. I have 3 injector filters with my extra o-rings and spacers. I'll swap that out as well......just in case.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Shuddering engine...UPDATE July,1

Reply #125 –
Curious, where did you find your STI wire?

Shuddering engine...UPDATE July,1

Reply #126 –
It was in the large plug, and not stand alone as I've always seen before.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Shuddering engine...UPDATE July,1

Reply #128 –
Definitely going to echo compression test myself. That or of course you could rotate that cylinder to TDC and try to force compressed air through the spark plug hole, if you can seal it somehow, and listen for air hissing. But just do a compression test LOL. If you had an exhaust valve not closing all the way, it would probably backfire constantly/might have a "thwuh thwuh thwuhh" sound out of that side tailpipe, and of course leaking intake valve would cause intake popping. Lean/rich conditions can cause random backfiring. Screwed up TIMING can too, when you rev it way up in neutral anyhow. I know this because I just got the red car back on the road, and I had exaclty zero advance, balancer was set at TDC. And that's what it did lol. Not to mention absolutely no power at all.
 
The plug has surely been in the car, running right for too long, you probably won't notice any foul deposits on it that immediately be a smoking gun. Lou is right on the money with those codes, interesting one about the fuel pump monitor, learn something new every day!
1987 20th Anniversary Cougar, 302 "5.0" GT-40 heads (F3ZE '93 Cobra) and TMoss Ported H.O. intake, H.O. camshaft
2.5" Duals, no cats, Flowmaster 40s, Richmond 3.73s w/ Trac-Lok, maxed out Baumann shift kit, 3000 RPM Dirty Dog non-lock TC
Aside from the Mustang crinkle headers, still looks like it's only 150 HP...
1988 Black XR7 Trick Flow top end, Tremec 3550
1988 Black XR7 Procharger P600B intercooled, Edelbrock Performer non-RPM heads, GT40 intake AOD, 13 PSI @5000 RPM. 93 octane

Shuddering engine...UPDATE July,1

Reply #129 –
I rechecked the number 8 plug. It's black, not that tannish color as the others.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Shuddering engine...UPDATE July,1

Reply #130 –
Fouled with carbon, from running rich? Or un burnt oil?
'98 Explorer 5.0
'20 Malibu (I know, Chevy, but, 35MPG. Let's go brandon, eh)

Shuddering engine...UPDATE July,1

Reply #131 –
I'm going to get a replacement plug, and swap it out. After that, swap the injector. One at a time.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..

Shuddering engine...UPDATE July,1

Reply #132 –
Replace the plug, re-run Cylinder Balance.  If it's blackened, You're looking at this: Overfueling, or lack of spark. You DID just replace the wires, so if there was a lack of spark, you could have nailed it with the wire change, but been left with a fouled plug which would cause if to seem like the problem hadn't been fixed. 
Still, you can check it with a spark tester, you can get one at any parts store and they're cheap.  You may even have one already.  You want the one that snaps into the plug wire and clips to a ground.  I think Tom would be able to tell you better what to set the tester to, but I'd say you're safe if you can get the spark to jump when its set to 22KV.  Alternatively, you can still be overfueling #8, in which case, you'll still get a misfire, but that miss will follow the injector.  I'd recommend moving the injector to the front of the bank and rerun Cylinder Balance, to see if the miss is now on #4. Possible causes are a clogged pintle, or a dead injector.  You can also install a fuel pressure gauge and watch the ign off pressure as you ground the injector driver circuit for that injector.  You'll be watching for it to drop slightly when you've got the driver circuit grounded and the feed circuit powered (just a quick tap to ground). If fuel pressure drops, you'll have verified that the injector works, at which point you'll move on to a noid light to determine if the injector is being commanded properly.  First, with the key on, you'll connect your test light to ground and probe both wires in the injector connector. one should have power, the other should not.  If one has power, switch your test light to battery positive and poke the other pin in the connector, watch for the light to flash while the engine is cranking.  If it does, you've not only got injector power, but injector command.  Once the injector AND the circuits have been verified, perform manual compression on the affected cylinder.  I like to run compression with ALL the plugs out and the throttle open.  Crank for 5 revolutions, with the first rev being the most important (at least to me).
So you start by verifying ignition, then fuel delivery, then fuel control, then base engine.  If there's a problem in #8, this is how you'll find it.

Shuddering engine...UPDATE July,1

Reply #133 –
OK clearly number 8 is your GUY. You just might have a bad plug or injector. The compression or leak down test will clear up a cylinder issue. You can use an old spark plug to check spark at that cylinder by gaping an old plug at .100 and grounding it somewhere on the block with the number 8 wire connected to it of course and start the engine. Look for a blue color spark and it should have a distinct snap. The compression will be the KEY. If it is within specks and close to other cylinders you are GOLDEN. If not you will have to call the neighborhood PIZZA store for your favorite pies and beverage. The head will have to come off. Hope not but not the end of the world. You just might have a bad plug or wire. Even though they are new they could be bad. IT HAPPENS.

ALSO check the cap for tracking on number 8 it just might have a crack in it. Look closely and check it carefully
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

Shuddering engine...UPDATE July,1

Reply #134 –
I work another 12 hour shift today. I'll get some work done asap and report back. Keep your fingers crossed, and thanks.
'88 Sport--T-5,MGW shifter,Trick Flow R intake,Ed Curtis cam,Trick Flow heads,Scorpion rockers,75mm Accufab t-body,3G,mini starter,Taurus fan,BBK long tube headers,O/R H-Pipe, Flowamaster Super 44's, deep and deeper Cobra R wheels, Mass Air and 24's,8.8 with 3.73's,140 mph speedo,Mach 1 chin spoiler,SN-95 springs,CHE control arms,aluminum drive shaft and a lot more..