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Cold engine sputtering. Not sure where to start. Howell TBI, DUI.

dyldebus

Legacy Registered User
City
Encinitas
State
CA
Hey guys, I have a 258 with only 76k miles and I've installed a Howell TBI unit as well as a DUI distributor. All the vacuum lines have been replaced.

I have a sputter, it's most apparent when first starting a cold engine (as in the video). When it's warm out or when the engine is warmed up and restarted, it seems to go away.

Any ideas where to start? My charcoal canister & egr are both original and my PCV valve seems to fit looser that I think it should but other than that my vacuum lines are solid. I haven't done a smoke test for any leaks though.

[video=youtube;flaXuj44dXM]https://www.youtube.com/watch?v=flaXuj44dXM&spfreload=10[/video]

I don't have an ODB1 scanner for the howel but the light doesn't come on (except in accessory mode). Would it throw codes without lighting up?

Thanks,
Dylan
 

walkerhoundvm

Just trying to stay upright
Lifetime Member
City
Cave Creek
State
AZ
Are you running the original intake manifold as well? Original air cleaner?

How long have you had the TBI and is this the first winter season it's been doing it?

Mine does it a little when really cold, too. I'm talking <50* and down to 0* here. It does it worse when really cold. My feeling is that it's related to the temperature of the intake manifold, and the function of the heater element on the manifold. My circuits are toast now, the heating element is run off of some jack-organized connection involving one of the original carb circuits and the reverse light for who knows what reason. Someone cut the carb circuit and that basically upset my whole system - no functioning heater element and no functioning reverse light until I disconnected the oil pressure shut-off connection.

I know, right? So now I have a working reverse light, but still a non-functional heating element. When I rigged the heating element up to a switch direct from the battery, the TBI ran fine. That was a hassle because it was another thing to forget to turn off either on the way to work or when I got to work, and it's a serious power drain to boot. I ditched the switch and deal with a little bit of initial sputter until I get the energy to try to rebuild that heater element circuit...
 

walkerhoundvm

Just trying to stay upright
Lifetime Member
City
Cave Creek
State
AZ
And actually I know the reason - the oil pressure circuit basically tells the carb circuit and the reverse light (as well as the heater element) when the car is running - so all are only functional when you actually have power to the oil pressure sending unit. There's a relay that shuts the intake heating element on initially, then off when the temperature sensor reaches 165* or whatever it's programmed for. That relay was long gone when I purchased my CJ...
 

dyldebus

Legacy Registered User
City
Encinitas
State
CA
Thanks for the replies. I should clarify that my "Cold" is roughly 50º F at the coldest (San Diego). I am running the original intake but I recently replaced the exhaust manifold/gasket. Air cleaner is an after market Air Raid unit for the Howel.

I'm pretty sure my timing is accurate but I've always been confused when setting timing. My process is to unplug vacuum from the DUI and plug the hose with a screw driver. Then I do the jumper thing with the howel computer (although this changes nothing whether I do it or not) and then I set the timing to roughly 8º BTDC. I do all this at idle speed. My RPMS usually end up around 700 at idle (1100 when cold starting).

My timing indicator has no numbers on it but I just count the notches at match this diagram:
0900c1528004ae0e.gif
 

dmock

Jeep junkie...CJ8, JK
Lifetime Member
City
Gun Barrel City
State
TX
You can see the diagnostic codes by jumping the computer connector and turning the key on and off three times. The check engine light will flash the codes. If I remember right..if you look in the Howell instructions they out line how to do this. You will need the fault codes for the system as well. Could be idle air control or map sensor...
 

mysunnshine

Legacy Registered User
City
Phoenix
State
AZ
It sounds like a spark plug is fouled or a plug wire not connected well/broken.
 

dyldebus

Legacy Registered User
City
Encinitas
State
CA
@dmock, Thanks! I didn't know this. I'll give that a shot first.

@mysunnshine If the codes turn out to be nothing then I'll replace my plugs and see if that helps. Is there a way to test the spark plug wires? I can't imagine they're bad, I purchased some nice ones with the DUI install.

Thanks guys, I'll have some time this Saturday to get in there.
 

CBRogers

Perpetual Parts Collector
Lifetime Member
City
Yorktown
State
Va
Check the water temp sensor too. That sensor if bad will cause it to run really rich if I remember right. Might be that the wire got knocked off or something. It is an easy check.


Carl
 

dyldebus

Legacy Registered User
City
Encinitas
State
CA
It turned out to be the plugs. I pulled all 6 and they actually looked fine. They were all gapped to 45 (per DUI instructions) so I wasn't confident that changing them would do anything.

I put in some Autolite 995 Copper Plugs and voila! No more issues. It was purring like a kitten in all conditions.

I originally sprang for some fancy platinum plugs but it turns out that the good ol' copper plugs are the way to go. I do have a stock coil so I'm not putting down the platinum but they definitely didn't work for me.

I also gapped the copper plugs to 40 instead of 45.

Thanks for the help!
 

boyd

Basic User
City
crestview,FL.
State
Fl
I'm having the same problem, engine has about 110 mi. on new rebuild, has champion plugs. you said you used autolite995 copper, can't seem to find a 995 listed? Is this correct/ thanks. And the gap I have a 40,000 volt dist that I changed out from a dui 50,000 & I think I gap them at 40 or 45
 
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