4.0 aint running right

[Jackrabbit41]

1987 Renix 4.0.

It sat for a month and I went to start it and it hardly runs and I drove it 50 feet to my driveway and it died 7 times. I have fuel pressure ( just checked it by pushing the bleeder), I gave it a tune up ( New spark plugs, wires and cap), spark is good, did the fuel filter, nothing ever made it better. Not sure where to go from here. Owned this thing 7 years and I never have to work on the motor so really not sure where to go. My vaccum lines look good too, and I tried unplugging the IAC and when I did that nothing changed so thinking maybe thats bad? Thanks yall

[Fernando87mj]

How’s the quality of the fuel ? I know it’s only been a month but I don’t have much faith In the stuff they put in fuel 

 

 and remember even though you got some fuel by depressing the Schrader valve on the fuel rail doesn’t eliminate the fact that your fuel pump might not be supplying sufficient pressure.

[MiNi Beast]

Cps or tps. 

[MiNi Beast]

Check fuel ballast as well. 

[Jackrabbit41]

51 minutes ago, Fernando87mj said:

How’s the quality of the fuel ? I know it’s only been a month but I don’t have much faith In the stuff they put in fuel 

 

 and remember even though you got some fuel by depressing the Schrader valve on the fuel rail doesn’t eliminate the fact that your fuel pump might not be supplying sufficient pressure.

Its from just some random gas station in town so I really don't know but I dummed three cans of sea foam in it lol 

[Jackrabbit41]

13 minutes ago, MiNi Beast said:

Check fuel ballast as well. 

What is that? Where is that? What does it look like? if you don't mind answering a stupid question that I could look up on google lol just like hearing it from someone 

[Jackrabbit41]

14 minutes ago, MiNi Beast said:

Cps or tps. 

Isnt the cps just spark? Ive gone through that a few years ago when I did my tranny for the 3rd time and it jsut caused no spark, but I have plenty of spark

[MiNi Beast]

Fuel ballast is a small white 2 blade on the driver's fender in the engine bay. It's a resistor to save your fuel pump. Sometimes corroded and may need to be replace. Can be jumped for verification.  

Crank sensor retards the timing or something but it reads your flywheel and sends a signal to to spark when injector injects fuel. Timing is key to ensure it runs smoothly. Typically you will have a idle but under load it runs like crap when bad.

Throttle position sensor controls the Throttle bodie so if not having a steady idle and or high idle, this can be a issue.

You could explain 🤔 a bit more on what is going per say and we could get you closer perhaps but this be where I would start with you having good spark and fuel. Question being are you getting spark and fuel at the right time.. 

So double check your wires being right order. Might just be that simple. 🤔

 

No stupid questions here good sir. This is what the site is all about. 

[Jackrabbit41]

6 minutes ago, MiNi Beast said:

Fuel ballast is a small white 2 blade on the driver's fender in the engine bay. It's a resistor to save your fuel pump. Sometimes corroded and may need to be replace. Can be jumped for verification.  

Crank sensor retards the timing or something but it reads your flywheel and sends a signal to to spark when injector injects fuel. Timing is key to ensure it runs smoothly. Typically you will have a idle but under load it runs like crap when bad.

Throttle position sensor controls the Throttle bodie so if not having a steady idle and or high idle, this can be a issue.

You could explain 🤔 a bit more on what is going per say and we could get you closer perhaps but this be where I would start with you having good spark and fuel. Question being are you getting spark and fuel at the right time.. 

So double check your wires being right order. Might just be that simple. 🤔

 

No stupid questions here good sir. This is what the site is all about. 

It used to idle fine but wouldn’t move under load very well. Now, as in today, it hardly starts and when it does start it sputters then dies. To me the motor sounds like it’s not getting fuel but I'm really not sure. I will check what you said tokorrow after work 

[MiNi Beast]

Cps is always my guess 

[87MJTIM]

9 hours ago, MiNi Beast said:

Fuel ballast is a small white 2 blade on the driver's fender in the engine bay. It's a resistor to save your fuel pump. Sometimes corroded and may need to be replace. Can be jumped for verification.  

Crank sensor retards the timing or something but it reads your flywheel and sends a signal to to spark when injector injects fuel. Timing is key to ensure it runs smoothly. Typically you will have a idle but under load it runs like crap when bad.

Throttle position sensor controls the Throttle bodie so if not having a steady idle and or high idle, this can be a issue.

You could explain 🤔 a bit more on what is going per say and we could get you closer perhaps but this be where I would start with you having good spark and fuel. Question being are you getting spark and fuel at the right time.. 

So double check your wires being right order. Might just be that simple. 🤔

 

No stupid questions here good sir. This is what the site is all about. 

 

87s did come with ballast resistors, originally.  They may have been added by the dealer after a factory TSB about the noise of the fuel pump.  Mine does not have one.  I got a parts 87 XJ that had a dealer installed BR.

[scaleless]

2 hours ago, 87MJTIM said:

They may have been added by the dealer after a factory TSB about the noise of the fuel pump.

I believe the ballast was added in midway through the '88 model year, so it all depends on if their '87 was brought in for service after that bulletin.

[rokinn]

Are you getting exhaust flow?  Critters nesting in the tail pipe? 

[Jackrabbit41]

20 hours ago, MiNi Beast said:

Fuel ballast is a small white 2 blade on the driver's fender in the engine bay. It's a resistor to save your fuel pump. Sometimes corroded and may need to be replace. Can be jumped for verification.  

Crank sensor retards the timing or something but it reads your flywheel and sends a signal to to spark when injector injects fuel. Timing is key to ensure it runs smoothly. Typically you will have a idle but under load it runs like crap when bad.

Throttle position sensor controls the Throttle bodie so if not having a steady idle and or high idle, this can be a issue.

You could explain 🤔 a bit more on what is going per say and we could get you closer perhaps but this be where I would start with you having good spark and fuel. Question being are you getting spark and fuel at the right time.. 

So double check your wires being right order. Might just be that simple. 🤔

 

No stupid questions here good sir. This is what the site is all about. 

I don’t see any 2 blade white connectors. Is it that plug going into where those vaccums

lines are hooked up too? 

[jdog]

Have you done cruiser54.com tips 1-5 only other thing I have to add to check is your map sensor

[scaleless]

This is the fuel pump ballast.

 

 

It doesn't appear you have one.

 

But listen to Jdog - make sure you complete Cruiser's tips before you advance.

[cruiser54]

Fuel pressure has not been verified with a gauge!!

Let's quit guessing. 

If fuel pressure was good, it woulda sprayed the piss outta the OP. 

 

The Tips are always a must to do and are free. 

CPS is generally no start and no spark.

 

As for the ballast resistor, it is NOT to save your fuel pump.

It allows the fuel pump to get 12 volts when cranking, but about 9 volts when running.

That keeps the pump QUIET and was the only reason the factory equipped the Jeeps that way and came out with a retro-fit to address customer complaints. 

 

The crank sensor does NOT retard the timing. It READS the flywheel slots only and sends an AC voltage signal to the ECU.

 

All that crap straightened out I hope.

 

Try starting fluid and see what happens. Down and dirty way to see if it's a fuel issue. 

[MiNi Beast]

2 hours ago, cruiser54 said:

Fuel pressure has not been verified with a gauge!!

Let's quit guessing. 

If fuel pressure was good, it woulda sprayed the piss outta the OP. 

 

The Tips are always a must to do and are free. 

CPS is generally no start and no spark.

 

As for the ballast resistor, it is NOT to save your fuel pump.

It allows the fuel pump to get 12 volts when cranking, but about 9 volts when running.

That keeps the pump QUIET and was the only reason the factory equipped the Jeeps that way and came out with a retro-fit to address customer complaints. 

 

The crank sensor does NOT retard the timing. It READS the flywheel slots only and sends an AC voltage signal to the ECU.

 

All that crap straightened out I hope.

 

Try starting fluid and see what happens. Down and dirty way to see if it's a fuel issue. 

I will always explain it as retards it as makes the most sense to me. Still say cps.  but thanks for the technical support. 

[cruiser54]

2 hours ago, MiNi Beast said:

I will always explain it as retards it as makes the most sense to me. Still say cps.  but thanks for the technical support. 

Won't have spark if CPS is bad!!

You are GUESSING it's the CPS even when there is evidence that it's not. 

And how can something that generates a signal like a CPS retard the timing? 

 

Do you not feel any accountability/responsibility to those asking for advice? 

Is their time and money not important to you? 

 

These people are relying on us for good advice, not guesses. Hell, THEY can guess just as well as we can. 

[scaleless]

1 minute ago, cruiser54 said:

And how can something that generates a signal like a CPS retard the timing? 

 

I assume he's vaguely referring to the regular vs. high altitude CPS but doesn't really understand how that advances the timing.

[cruiser54]

Who knows? 

[MiNi Beast]

1 hour ago, cruiser54 said:

Won't have spark if CPS is bad!!

You are GUESSING it's the CPS even when there is evidence that it's not. 

And how can something that generates a signal like a CPS retard the timing? 

 

Do you not feel any accountability/responsibility to those asking for advice? 

Is their time and money not important to you? 

 

These people are relying on us for good advice, not guesses. Hell, THEY can guess just as well as we can. 

I take full accountability for helping members solve their issues. Any input to me on the internet helps one go through many things that can cause the issues. More so when new members are just getting started, like me when I got started, I listened to anything that might get me to the root of the issue. I didn't say go buy this or that, so that's on the certified parts changer. I just often suggest things as it's explained to me and help best I can. Last time you had issues with my cps suggestion, it stilled ended up being cps. May not be here, and I have had bad cps with intermediate voltage signal,  so scan tool read it to be ok, but go figure it still was bad. Again I appreciate your technical support as good to understand the proper terms of how things work or are called. I let you handle that being you have your own website and all, however, I just assume continue as my advice has helped many narrow things down if not fixed the issue all together. So what do I know I'm just a guy with a jeep that has yet to perform any of your tips.  Good day sir, feel free to agree to disagree cause I'm to busy enjoying life to give 2 $#!&z. 

[cruiser54]

That's my point. You don't give 2 $#!&s if you waste people's time and money by dropping half-assed answers in threads and then go on "enjoying life" afterwards.

 

What about THEM?

[MiNi Beast]

51 minutes ago, cruiser54 said:

That's my point. You don't give 2 $#!&s if you waste people's time and money by dropping half-assed answers in threads and then go on "enjoying life" afterwards.

 

What about THEM?

Oh so now my opinion doesn't mean anything eh? That's not very club friendly. To be clear it was I don't give two $#!&z for your responses to my, as you say 'half answers', or how you might feel about my input. You don't like it, keep providing your input and lead everyone away from the club site to your personal site prick. 

[MiNi Beast]

2 hours ago, scaleless said:

 

I assume he's vaguely referring to the regular vs. high altitude CPS but doesn't really understand how that advances the timing.

Doesn't advance the timing, it reads the flywheel telling cpu to fire at right time in correlation to fuel injector impulses and spark from distributor. So it dumb down speak for anyone not up on the technical terms, need all three with proper airflow to work. But I'm no expert and am nobody, so read into all you want. If want some technical support and get somewhere go pay for diagnostics. Or feel free to PayPal me when you find out what it is. Thanks have a great day cause I am. Or I'm sorry, just cause I'm having a great day doesn't mean you will either. My bad.