AMC 258 w/ Holley carb: Engine Won't Start - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > General Technical Discussions > Engines & Drivetrain > AMC 258 w/ Holley carb: Engine Won't Start

NEW JK WRANGLER GRAB BARS NOW at ROCKRIDGE4WDRear Disc Brake Conversion Kit- TJ,YJ,XJSWAG 50 Cal Ammo Can Mount With M2A1 Can

Reply
Unread 01-12-2005, 09:34 AM   #1
Infedel
Registered User
 
Join Date: Apr 2002
Location: Washington
Posts: 87
AMC 258 w/ Holley carb: Engine Won't Start

I think I’m having carb problems. Engine won’t start. I checked the #1 plug, and it’s sparking. I checked plugs 1-4 and according to the timing light, they are getting spark from the distributor.
If I pull the throttle on the carb, the jets squirt fuel. When I try to start the engine, it cranks (but not ignition). If I try and load in fuel (push the gas pedal), the engine will bog down, and have a difficult time turning over. Eventually, the fuel blows back out through the carb and it gets a nice “poof” or “bang”.
Initially, I thought that the gas wasn’t being ignited in the cylinder, but if the plugs are sparking, then there should be some sign of ignition, right? I’m wondering if either the carb isn’t passing the fuel through the manifold, or if there is a loss of vacuum in the engine that isn’t pulling the fuel into the cylinder.
Engine is an AMC 258. Offenhauser Intake Manifold and Holley 4-barrell 390CFM carb.

__________________
'84 CJ-7
AMC 258 Stroker
Centerforce II Clutch
1" Body Lift
1" Shackle Lift
33x12.5" SSR Tires
Painless Wiring, Stainless Steel Dash
Infedel is offline   Reply With Quote
Unread 01-12-2005, 11:56 AM   #2
LT1CJ7
Registered User
1983 CJ7 
 
Join Date: Aug 2004
Location: [duhm-as]
Posts: 4,512
Quote:
Originally Posted by Infedel
the fuel blows back out through the carb and it gets a nice “poof” or “bang”.
It sounds like your timing is out, or your firing order is wrong.
LT1CJ7 is offline   Reply With Quote
Unread 01-12-2005, 12:24 PM   #3
Infedel
Registered User
 
Join Date: Apr 2002
Location: Washington
Posts: 87
I verified the firing order. It's correct.
Using the timing gun, the tick-mark shows that the timing should be correct.
A friend mentioned that the chain may have slipped somehow, this would leave the appearance that timing was correct, but really wasn't. This might explain why there is blow-back through the carb.
__________________
'84 CJ-7
AMC 258 Stroker
Centerforce II Clutch
1" Body Lift
1" Shackle Lift
33x12.5" SSR Tires
Painless Wiring, Stainless Steel Dash
Infedel is offline   Reply With Quote
Unread 01-12-2005, 09:53 PM   #4
Infedel
Registered User
 
Join Date: Apr 2002
Location: Washington
Posts: 87
Update

New distributor and plugs (plugs didn't change anything, distributor did). Idles nice and smooth, even revs real evenly.
Went for a test drive, and at low RPM, the engine would bog down, sputter and try to die. I had to keep the RPM's high and ride the clutch to get it up the small hill of my driveway.
At idle, it sounds great, but the timing mark is way off of the mark. I can't even begin to get it close to in spec without bringing the idle RPM so low that the engine dies.
Has anyone ever had a timing chain slip before?
__________________
'84 CJ-7
AMC 258 Stroker
Centerforce II Clutch
1" Body Lift
1" Shackle Lift
33x12.5" SSR Tires
Painless Wiring, Stainless Steel Dash
Infedel is offline   Reply With Quote
Unread 01-13-2005, 06:40 AM   #5
gosupes
Registered User
1986 CJ7 
 
Join Date: Jun 2004
Location: Monroe, WA
Posts: 1,526
Two thoughts. If the timiing has slipped like you think it might have, I wouldn't run it until I checked. If it were to slip another tooth, there is a chance the pistons could slap into the valves. Also what vacuum source are you using for the dist?
__________________
1986 CJ7, 4.2 w/4.0 head, TFI-HEI hybrid ignition, Clifford manifold w/Holley 390 w/cold air intake, OBA, 4.5" lift, Woody CV shaft and Tattons in front, 4.10 gears - lunchbox in front, Truetrac in the back, twin-sticked, blower upgrade for running topless, trying to keep it simple.

It's just a Jeep, and if you don't wheel it once in a while, it's not even that.
gosupes is online now   Reply With Quote
Unread 01-13-2005, 11:57 AM   #6
Infedel
Registered User
 
Join Date: Apr 2002
Location: Washington
Posts: 87
Vacuum Source

The Vacuum source for the disti comes from the Holley carb.
It's my understanding that this should be advancing the timing, however the MSD iginition is also suppose to be doing this. I'm wondering if there is a conflict... MSD is advancing the spark when the accelerator is pushed, while ht ecarb is trying to physcially advance the distributor withe the vacuum. I'll try disconnecting the carb vacuum tonight.
A thought is that the vacuum is trashed on the carb (leak somewhere). It all use to work well toghter.
__________________
'84 CJ-7
AMC 258 Stroker
Centerforce II Clutch
1" Body Lift
1" Shackle Lift
33x12.5" SSR Tires
Painless Wiring, Stainless Steel Dash
Infedel is offline   Reply With Quote
Unread 01-13-2005, 01:36 PM   #7
gosupes
Registered User
1986 CJ7 
 
Join Date: Jun 2004
Location: Monroe, WA
Posts: 1,526
I was just wondering whether the vacuum source was ported or manifold vacuum. If you can't see the timing mark you will need to get or borrow a timing light with an adjustable advance.
__________________
1986 CJ7, 4.2 w/4.0 head, TFI-HEI hybrid ignition, Clifford manifold w/Holley 390 w/cold air intake, OBA, 4.5" lift, Woody CV shaft and Tattons in front, 4.10 gears - lunchbox in front, Truetrac in the back, twin-sticked, blower upgrade for running topless, trying to keep it simple.

It's just a Jeep, and if you don't wheel it once in a while, it's not even that.
gosupes is online now   Reply With Quote
Unread 01-14-2005, 10:29 AM   #8
Infedel
Registered User
 
Join Date: Apr 2002
Location: Washington
Posts: 87
Update

I have a timing light. I can see the mark, it's just way the heck off. About 2 inches south of where it should be.
Last night i tried a new carb, but that didn't really help much (Holley Truck Avenger).
This morning i pulled the dip-stick. There was a white slime on it.
A few weeks ago, I replaced the rear main seal. As recomended, i used a little dish soap to slip the new seal in (couldn't have done it otherwise). Possibly got a little soap mixed wth the oil.

When i ran it around the block the other night, the engine was quite quick to overheat. I hadn't seen it do that before. Seems to be losing water (i had to put in half-gallon last night). Also, the heater stopped working last month as well. Friend is thinking that the head gasket might have blown. I'm thinking worse (cracked block) right now.

Any recomendations on how to proceede?
__________________
'84 CJ-7
AMC 258 Stroker
Centerforce II Clutch
1" Body Lift
1" Shackle Lift
33x12.5" SSR Tires
Painless Wiring, Stainless Steel Dash
Infedel is offline   Reply With Quote
Unread 01-14-2005, 09:57 PM   #9
gosupes
Registered User
1986 CJ7 
 
Join Date: Jun 2004
Location: Monroe, WA
Posts: 1,526
You have water in the oil. Head gasket woould be the first place to check. BTW, how did bore the 258 to 4.9?
__________________
1986 CJ7, 4.2 w/4.0 head, TFI-HEI hybrid ignition, Clifford manifold w/Holley 390 w/cold air intake, OBA, 4.5" lift, Woody CV shaft and Tattons in front, 4.10 gears - lunchbox in front, Truetrac in the back, twin-sticked, blower upgrade for running topless, trying to keep it simple.

It's just a Jeep, and if you don't wheel it once in a while, it's not even that.
gosupes is online now   Reply With Quote
Unread 01-15-2005, 10:07 AM   #10
Infedel
Registered User
 
Join Date: Apr 2002
Location: Washington
Posts: 87
It's a stroker.
__________________
'84 CJ-7
AMC 258 Stroker
Centerforce II Clutch
1" Body Lift
1" Shackle Lift
33x12.5" SSR Tires
Painless Wiring, Stainless Steel Dash
Infedel is offline   Reply With Quote
Unread 01-16-2005, 07:09 AM   #11
gosupes
Registered User
1986 CJ7 
 
Join Date: Jun 2004
Location: Monroe, WA
Posts: 1,526
That's what I thought but I never bother to read your sig but most people list them as a stroked 4.0. Maybe that's where the problem is, bored it out a little too close to a water jacket. Either way, doesn't sound good.
__________________
1986 CJ7, 4.2 w/4.0 head, TFI-HEI hybrid ignition, Clifford manifold w/Holley 390 w/cold air intake, OBA, 4.5" lift, Woody CV shaft and Tattons in front, 4.10 gears - lunchbox in front, Truetrac in the back, twin-sticked, blower upgrade for running topless, trying to keep it simple.

It's just a Jeep, and if you don't wheel it once in a while, it's not even that.
gosupes is online now   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.