no power

A

al chernoff

New member
Oct 11, 1999
737
0
0
Did Statkus give you any advise when he checked your engine?
I dont know about engines, but the cylinders look like they are supposed
to. I was told that a 20% variance was ok and yours seem to be that way.
I am going to Statkus to test my engine. I do not have the caspro trans,
but I do have the cinnibar 3.42 final drive. I do have bigger tires,
235/85/16 so I expect some degridation in the tires being bigger. Did
your EFI show anything when it was tested?

When you find what fixes the problem, let me know.
Al

> [Admin note - "Bounced" multi-part HTML encoded. Jerry, please post in
> plain text only to GMCnet. Thanks! Patrick]
>
> Perhaps someone could give me some ideas for my problem. I went to a
> shop to have a gas analysis and scope done to maybe find the reason for
> a lack of power.
>
> Hydrocarbons were above 900 and number 2 and 3 cycinders would not
> cancel. This is a 455 with Howell tbi. (also have Caspro power drive,
> Thorley headers, and Jardine 3" exhaust). The engine has 6,000 miles on
> rebuild. This thing should leap tall buildings!!!!!!! It actually
> pulled better before all the goodies. Compression checks are as
> follows:
>
> COLD #1-143 #2-129 #3-139 #4-135 #5-133 #6-130 #7-135 #8-135
> HOT #1-140 #2-135 #3-140 #4-139 #5-139 #6-135 #7-136 #8-139
>
> Timing is at 10 degrees initial and a new Caspro HEI distributor with
> plug gap set at 60. Vacuum is 18" at idle but drops to around 3 " in
> hard pull. At 60 on flat ground vacuum is about 10". I swapped plug
> wires and then plugs between #2 and #1 but #2 still does not cancel .
> Pull #1 plug wire and RPM drops but pull #2 plug wire and no change in
> RPM. Same with #3.
>
> Anybody have any suggestions?
>
> Jerry
 
[Admin note - "Bounced" multi-part HTML encoded. Jerry, please post in
plain text only to GMCnet. Thanks! Patrick]

Perhaps someone could give me some ideas for my problem. I went to a
shop to have a gas analysis and scope done to maybe find the reason for
a lack of power.

Hydrocarbons were above 900 and number 2 and 3 cycinders would not
cancel. This is a 455 with Howell tbi. (also have Caspro power drive,
Thorley headers, and Jardine 3" exhaust). The engine has 6,000 miles on
rebuild. This thing should leap tall buildings!!!!!!! It actually
pulled better before all the goodies. Compression checks are as
follows:

COLD #1-143 #2-129 #3-139 #4-135 #5-133 #6-130 #7-135 #8-135
HOT #1-140 #2-135 #3-140 #4-139 #5-139 #6-135 #7-136 #8-139

Timing is at 10 degrees initial and a new Caspro HEI distributor with
plug gap set at 60. Vacuum is 18" at idle but drops to around 3 " in
hard pull. At 60 on flat ground vacuum is about 10". I swapped plug
wires and then plugs between #2 and #1 but #2 still does not cancel .
Pull #1 plug wire and RPM drops but pull #2 plug wire and no change in
RPM. Same with #3.

Anybody have any suggestions?

Jerry
 
Hummmmm
I do not understand what "2 and 3 will not cancel" I guess I do not
understand the analyzer. Mondello sets the spark advance at 25 degrees
total advance. That is over 2000 rpm. Did they play with the advance ??
Also, did you look in the throat of the intake?? You should be able to see
the two injectors working. Maybe you had only one ?? I know Mr.c had poor
power and found a bad injector.

so what is "will not cancel"?? Sounds like a great thing to do, put it up
on an analyzer.

gene

>[Admin note - "Bounced" multi-part HTML encoded. Jerry, please post in
>plain text only to GMCnet. Thanks! Patrick]
>
>Perhaps someone could give me some ideas for my problem. I went to a
>shop to have a gas analysis and scope done to maybe find the reason for
>a lack of power.
>
>Hydrocarbons were above 900 and number 2 and 3 cycinders would not
>cancel. This is a 455 with Howell tbi. (also have Caspro power drive,
>Thorley headers, and Jardine 3" exhaust). The engine has 6,000 miles on
>rebuild. This thing should leap tall buildings!!!!!!! It actually
>pulled better before all the goodies. Compression checks are as
>follows:
>
>COLD #1-143 #2-129 #3-139 #4-135 #5-133 #6-130 #7-135 #8-135
>HOT #1-140 #2-135 #3-140 #4-139 #5-139 #6-135 #7-136 #8-139
>
>Timing is at 10 degrees initial and a new Caspro HEI distributor with
>plug gap set at 60. Vacuum is 18" at idle but drops to around 3 " in
>hard pull. At 60 on flat ground vacuum is about 10". I swapped plug
>wires and then plugs between #2 and #1 but #2 still does not cancel .
>Pull #1 plug wire and RPM drops but pull #2 plug wire and no change in
>RPM. Same with #3.
>
>Anybody have any suggestions?
>
>Jerry
>
>
>
Genef -- 77PB/ore/ca
GMC MOTORHOME INFORMATION
mr.erf
http://www.california.com/~eagle/
 
I swapped plug
wires and then plugs between #2 and #1 but #2 still does not cancel .
Pull #1 plug wire and RPM drops but pull #2 plug wire and no change in
RPM. Same with #3.

Anybody have any suggestions?

Jerry

I'm not familiar with the terminology "cancel;" do you mean make the engine
miss?

I have found generally when two cylinders are "dragging their feet" and it
can't be ascribed to ignition, as yours apparently can't, and compression is
normal, as yours apparently is, that a serious vacuum leak is usually the
culprit. See if #2 and #3 aren't on the same, connected intake runner.
That's what I've seen in the past. I think if you look that you'll see #2
and #3 connected by a runner, #1 and #4 connected, #5 and #8, and #6 and
#7. A bad vacuum leak, say at the manifold/cylinder head interface, will
affect the two connected cylinders.

Travis in Lubbock, Texas
 
Jerry,

The key is that it worked better before you started playing with it! It
would have been better to add stuff one at a time to find out the full
potential of each addition one at a time. What you are faced with now are
several variables to sort out the trouble.

Sounds like timing and/or fuel mix. Double check to be sure wires are not
crossed or damaged. Inspect all ignition components to be sure there is no
aparent physical damage. Adj. your carb. with its new lungs attached.
Set the timing to 8 deg. with a timing light and then get out on the road
and time it on the fly.

If all of that yealds no fruit, while under load driving, cover a portion
of the carb. input and see what happens. If things get worse, mist a bit
of fuel into the carb. under the same load driving and see what happpens.

If still no go, now this is pretty drastic- Start replacing the dist. and
whatever you upgraded with the OEM parts one at a time until the thing runs
better. Decide then wether to leave it that way or find out why the
upgraded part screwed up your performance.

If this even fails, dig a hole and burry the monster head first!!!

Good luck,

Jim Bounds
- ----------------------

>[Admin note - "Bounced" multi-part HTML encoded. Jerry, please post in
>plain text only to GMCnet. Thanks! Patrick]
>
>Perhaps someone could give me some ideas for my problem. I went to a
>shop to have a gas analysis and scope done to maybe find the reason for
>a lack of power.
>
>Hydrocarbons were above 900 and number 2 and 3 cycinders would not
>cancel. This is a 455 with Howell tbi. (also have Caspro power drive,
>Thorley headers, and Jardine 3" exhaust). The engine has 6,000 miles on
>rebuild. This thing should leap tall buildings!!!!!!! It actually
>pulled better before all the goodies. Compression checks are as
>follows:
>
>COLD #1-143 #2-129 #3-139 #4-135 #5-133 #6-130 #7-135 #8-135
>HOT #1-140 #2-135 #3-140 #4-139 #5-139 #6-135 #7-136 #8-139
>
>Timing is at 10 degrees initial and a new Caspro HEI distributor with
>plug gap set at 60. Vacuum is 18" at idle but drops to around 3 " in
>hard pull. At 60 on flat ground vacuum is about 10". I swapped plug
>wires and then plugs between #2 and #1 but #2 still does not cancel .
>Pull #1 plug wire and RPM drops but pull #2 plug wire and no change in
>RPM. Same with #3.
>
>Anybody have any suggestions?
>
>Jerry
>
>
>
>
 
>
> Hydrocarbons were above 900 and number 2 and 3 cycinders would not
> cancel. This is a 455 with Howell tbi. (also have Caspro power drive,
> Thorley headers, and Jardine 3" exhaust). The engine has 6,000 miles on
> rebuild. This thing should leap tall buildings!!!!!!! It actually
> pulled better before all the goodies.

High HC's and no change when you pull a plug wire sounds like a couple
of lame cylinders. Either poor mixture or ignition. If six of eight
cylinders are firing, check the distributor cap, wires and plugs. I'd
do a thorough troubleshoot of the Howell system - maybe put the carb
back on until you get the rest straightened out.

Good luck!
Patrick
- --
Patrick Flowers
Mailto:patrick

The GMC Motorhome Page
http://www.gmcmotorhome.com
 
[Admin note - "Bounced" multi-part HTML encoded. Jerry, you need to
post in "plain text" only to GMCnet. Patrick]

Well the vacuum leak was the cause of # 2 and #3 no cancel. That works
=
fine now. Still have a miss every one in a while that will most likely
=
clear up with a good ignition check(wires, plugs, rotor, cap etc.).
Thank you all for your suggestions and help!!
Jerry
 
Jerry... what is your vacuum now. Mine is still around 17 at idle and the
same as you indicated when running.
al

> [Admin note - "Bounced" multi-part HTML encoded. Jerry, you need to
> post in "plain text" only to GMCnet. Patrick]
>
> Well the vacuum leak was the cause of # 2 and #3 no cancel. That works
> fine now. Still have a miss every one in a while that will most likely
> clear up with a good ignition check(wires, plugs, rotor, cap etc.).
> Thank you all for your suggestions and help!!
> Jerry
 
I have now plugged the unused holes in the adapter plate for the Howell TBI.
My vacuum at idle went from 17 to 19 and #2 and #3 cancel out as they
should. Next step is test drive. Hopefully today. Will report results.
Jerry
 
You must log in or register to reply here.
Get your shine on at www.cruzingear.co
GMCMI Fall 2026 Rally

Share this page

Share this page
Top Bottom
Back