NEED HELP! 1986 720 Battery Shorted Out Against the Hood. Now Has Bad Engine Miss.....

[Yinzer]

Hey folks,

 

 I just picked up a nice 1986 720 4x4 KingCab. Sat in a barn the past 10 years. It has 195k on it.

 

 The truck was running fine until I turned a corner and the Positive Battery post shorted out against the underside of the hood. I had just bought the truck and didn't notice the PO put a battery in that was too tall. That and it was not secured very well. The engine sputtered and dieseled until it shut off completely.

 

 The truck would not start afterwards and I discovered a blown fuse (not sure which one). I replaced the fuse and it was hard to start, but did run if I held the RPMs up. It cuts out below 2000 RPMs and will not ide. The engine developed a bad low RPM miss.

 

I was near an O'Reillys so I had the battery and alternator checked out. The battery was a 65% and the alternator showed 13.0 Volts output. I replaced both the battery and alternator but the engine still has a bad low RPM miss and won't idle.

 

 I also replaced both Ignition Coils. Buddy said it sounds like it jumped time. I tried moving the distributor a bit (both ways) and got no improvement. 

 

 I'm suspecting the chain jumped time as well. I need to know is the Z24 and Interference engine or not. My research shows conflicting information. No clear answer.

 

 Now what ?
 

 TIA

[datzenmike]

The battery shorting to the hood would never cause the engine to jump a timing chain tooth, in fact there isn't enough slack to even do this. Yes it is an interference engine.

 

The trouble with replacing the coils is that now you have two coils that could be faulty and certainly of poorer quality.

 

Is there anything else on the truck that does not work electrically? that may have been caused by this 'short'?

 

 

Questions...

1/ Which fuse? Count over from left to right.

 

2/ Have someone turn the ignition between on and off several times, but  NOT START! You listen near the rear of the carburetor. You should hear a soft clicking sound, do you????

 

3/ Disconnect one of the intake side plug wires and put an old plug in the end. Hold against a grounded surface like the intake and have someone try to start the truck... is the spark???? Now do one on the exhaust side. Got spark on both sides????

 

[banzai510(hainz)]

my toyota the same thing previous owner put the in 180 off the shorted to the tie down bar then melted my parking brake cable insulation then more or less fry the parking brake cable as it eventually broke .  so it found a ground thru the brake cable when the smaller chassis grounds and alternator grounds fryed.

 

I took it in to have fixed but I noticed it would run at idle then when try to drive to would load up. I told the mechanic the grounds are most like melted.

sure as shit the  by the alternator harness ground was melted at the alternator. They found a new harness and spliced it in

Edited March 10, 2023 by banzai510(hainz)

[MikeRL411]

Classic example of why you need battery hold down!  Also why more modern vehicle designs include molded insulating covers on battery cable connectors,

[jagman]

On a car show run one of the cars dropped the battery and fried his capacitor making for a very weak spark. Could that be the case here Mike?

[Yinzer]

7 hours ago, datzenmike said:

The battery shorting to the hood would never cause the engine to jump a timing chain tooth, in fact there isn't enough slack to even do this. Yes it is an interference engine.

 

The trouble with replacing the coils is that now you have two coils that could be faulty and certainly of poorer quality.

 

Is there anything else on the truck that does not work electrically? that may have been caused by this 'short'?

 

 

Questions...

1/ Which fuse? Count over from left to right.

 

2/ Have someone turn the ignition between on and off several times, but  NOT START! You listen near the rear of the carburetor. You should hear a soft clicking sound, do you????

 

3/ Disconnect one of the intake side plug wires and put an old plug in the end. Hold against a grounded surface like the intake and have someone try to start the truck... is the spark???? Now do one on the exhaust side. Got spark on both sides????

 

 

Man....very relieve to hear it can't be the Timing chain. Sweating it all day thinking that. Thought my truck was toast. 

 

1) Fuse Number 2. Counting from the rear (nearest the door) to the front.

 

2) & 3)....   Have to wait until tomorrow to repair the fusible link connector that attaches to the Pos post. I accidently broke the brass piece manipulating the wires changing out the battery.

 

 The engine does seem to run ok about 2-3,000 RPMs. So it's getting spark there. The engine dies and won't idle after I let off the gas pedal and RPMs drop down.

 

 BTW, as a Newb, am I limited on posting up pics here ?

 

 

[Yinzer]

32 minutes ago, jagman said:

On a car show run one of the cars dropped the battery and fried his capacitor making for a very weak spark. Could that be the case here Mike?

 Does my truck have a Capacitor ? Isn't it Electronic Ignition ??

[Yinzer]

1 hour ago, MikeRL411 said:

Classic example of why you need battery hold down!  Also why more modern vehicle designs include molded insulating covers on battery cable connectors,

 

 No doubt! One of the first things I bought off Amazon. Arrived today. Need to install it ASAP.

[Yinzer]

4 hours ago, banzai510(hainz) said:

my toyota the same thing previous owner put the in 180 off the shorted to the tie down bar then melted my parking brake cable insulation then more or less fry the parking brake cable as it eventually broke .  so it found a ground thru the brake cable when the smaller chassis grounds and alternator grounds fryed.

 

I took it in to have fixed but I noticed it would run at idle then when try to drive to would load up. I told the mechanic the grounds are most like melted.

sure as shit the  by the alternator harness ground was melted at the alternator. They found a new harness and spliced it in

 

 I replaced the Alternator the next day on my truck. I didn't notice any wires/grounds burnt. New alternator works great.

[datzenmike]

57 minutes ago, Yinzer said:

 Does my truck have a Capacitor ? Isn't it Electronic Ignition ??

 

No capacitor.

 

 

 

8 hours ago, datzenmike said:

Questions...

 

 

2/ Have someone turn the ignition between on and off several times, but  NOT START! You listen near the rear of the carburetor. You should hear a soft clicking sound, do you????

 

3/ Disconnect one of the intake side plug wires and put an old plug in the end. Hold against a grounded surface like the intake and have someone try to start the truck... is the spark???? Now do one on the exhaust side. Got spark on both sides????

 

 

 

2/ this is a test to see if the idle cut solenoid is working. If not working gas can't get to the idle circuit. Won't idle below about 1,200 RPMs

 

3/ This tests that both coils are firing

[Yinzer]

16 hours ago, datzenmike said:

 

No capacitor.

 

 

 

 

2/ this is a test to see if the idle cut solenoid is working. If not working gas can't get to the idle circuit. Won't idle below about 1,200 RPMs

 

3/ This tests that both coils are firing

 

 Ok, I replaced all the Fusible links with same size wiring. Found one in a junk yard from a D21. Fired the truck up afterwards and NO change from the original problem.

 

 Also, the Idle Solenoid is clicking on/off so hopefully that is working ok.

 

 Now to check the firing of all 9 plugs and both coils. Will give another update in awhile.

 

 TIA

[datzenmike]

Well if the plug wire fires no need to check the coils.

[MikeRL411]

3 hours ago, Yinzer said:

 

 Ok, I replaced all the Fusible links with same size wiring. Found one in a junk yard from a D21. Fired the truck up afterwards and NO change from the original problem.

 

 Also, the Idle Solenoid is clicking on/off so hopefully that is working ok.

 

 Now to check the firing of all 9 plugs and both coils. Will give another update in awhile.

 

 TIA

9 plugs?

[datzenmike]

Miss keyed 8

[Yinzer]

1 hour ago, MikeRL411 said:

9 plugs?

 Actually dont know. Was too surprised finding what i needed and in a hurry to cut the wires out. Anyways, it had 5 Fusible links link mine and all the correct size wires. I spliced it in earlier today.  Yes, PAST the links. I didn't cut them.

[Yinzer]

Ok, I bought a spark plug tester...with a light element. ALL 8 plugs firing in a smooth pattern and all showed strong illumination.  Next step ??

[datzenmike]

So you can start it but it won't idle still?

[Yinzer]

Correct. Misses badly in low RPMs. Starts smoothing out around 2500 RPMs and smooths out more as RPMs increase. When I let off the throttle, it dies. Only way to keep the engine running is to hold the RPMs above 2500. I'm thinking to do a Compression Test next. Maybe blown head gasket perhaps ??

[datzenmike]

1/ At the back of the carburetor there is an electrical connector. Is it 3 or a round 6 pin connector???

 

2/ listen at back of carburetor while someone turns the ignition on off on off. You should hear soft clicking.

 

 

Check carburetor mounting bolts are snug. Check all hoses connected directly to the intake for cracks or leaks. Don't forget the hose to the booster. Perhaps pull each one off and close the port with your finger. Any improvement?

 

Does the EGR valve close? They can get carboned up and not seal. There is no EGR at idle so if not closing tight it sure won't idle very well.

 

[Yinzer]

10 hours ago, datzenmike said:

1/ At the back of the carburetor there is an electrical connector. Is it 3 or a round 6 pin connector???

 

2/ listen at back of carburetor while someone turns the ignition on off on off. You should hear soft clicking.

 

 

Check carburetor mounting bolts are snug. Check all hoses connected directly to the intake for cracks or leaks. Don't forget the hose to the booster. Perhaps pull each one off and close the port with your finger. Any improvement?

 

Does the EGR valve close? They can get carboned up and not seal. There is no EGR at idle so if not closing tight it sure won't idle very well.

 

 I checked the Idle Solenoid already (above). It clicks On/Off ok.

 

 There is NO EGR and/or any Emission junk left on the engine. The PO removed it all. Replaced the Carb with a New Remanufactured unit. He did a very good job of replacing/plugging up all the vacuum lines.

 

 The truck was running very good BEFORE the battery POS Terminal made contact with the underside of the hood. Immediately afterwards is when it started missing.

 

 I was making a turn into an O'Reilley's parking lot off a main road. I was going like 5 MPH while turning. The battery was NOT secured down properly and joust around when I hit ramp while turning causing the battery POS terminal to hit the hood.

 

 The engine spit and sputtered (I would say violently) then dieseled after the battery shorted against the hood. 

 

 I've only driven this truck maybe 10 miles since I bought it. PO delivered it via trailer to my place. I don't see/hear (other than bad Low RPM missing) of signs of a blown head gasket (what I'm kinda thinking...). The only indication maybe low water (yes pure water... PO had in the radiator). The truck does not have an overflow tank (Yet). I did check the water level in the radiator the day before and it was Full.

 

 I've seen no signs of OVERHEATING otherwise. The temperature gauge never above the Middle of the range. I've not looked (yet) to see any steam coming out the tailpipe. It wouldn't be white since there was no Coolant in it.

 

 That and the oil level is showing a 1/2 quart low. Thought that was odd since I checked it the day before and it showed 1/2 quart high. ??? Again, I've seen NO smoke (blue/white) or steam emitting from the tailpipe that I've noticed. I have no driven or had the engine running very long since the accident happened.

 

 I'm still perplexed..... thinking maybe the head gasket blew out when the battery shorted out against the hood. Don't know..... I'm doing a Compression test next.

 

 Is doing a Compression test on an 8 Plug 4 cylinder engine any different than a 4 plug 4 cylinder engine ?

 

TIA

Edited March 12, 2023 by Yinzer
add stuff

[datzenmike]

The dieseling could also have been miss firing or back firing through the carburetor. This will stir up sediment and that could have gotten into your idle circuit.

 

You have an electrical plug at the rear of the carburetor. Is it 3 wire or a larger round 6 wire plug??? There were two different carburetors I want to know which one you have.

 

Carefully unscrew the idle cut solenoid and lift away. Have a care as there is a spring and pin that will fall out. Direct a WD-40 straw into the idle cut opening ad spray liberally. This may dislodge any water of sediment back into the fuel bowl.

[Yinzer]

17 minutes ago, datzenmike said:

The dieseling could also have been miss firing or back firing through the carburetor. This will stir up sediment and that could have gotten into your idle circuit.

 

You have an electrical plug at the rear of the carburetor. Is it 3 wire or a larger round 6 wire plug??? There were two different carburetors I want to know which one you have.

 

Carefully unscrew the idle cut solenoid and lift away. Have a care as there is a spring and pin that will fall out. Direct a WD-40 straw into the idle cut opening ad spray liberally. This may dislodge any water of sediment back into the fuel bowl.

 Yes, it did backfire during the accident and does backfire occasionally now.

 

 I'll go clean the Idle Solenoid right now.

[Yinzer]

Ok. Just cleaned out the Idle Solenoid. Didn't see/feel any pieces of crud etc...

 

I also checked the power going to it with my Multimeter. All good. Getting 12 volt to it with the key in the ON position.

 

 

[Yinzer]

[Yinzer]

How the carb sits and looks is exactly as it was before the accident. As I said before, it was running good. No missing.