Jump to content

Cranks perfect after sitting two days, renix 4.0


Recommended Posts

So I've been trying to track down a cranking issue. Most people have slightly different issues than me.

 

If I don't drive the car for a full two days, it cranks right up every time in 2 seconds...

 

I want this all the time if I can get it.

 

If I let it sit for an hour, few hours, even wait until the next morning, it takes 7-8 seconds, maybe longer, to crank.

 

Does always crank, stumbles for half second, then iac pushes idle up and then back down. At this point it runs a little rough, I give it gas, and it seems better.

 

I've done all the main grounds from cruiser tips.

 

New map sensor, oem, with new tubing I made with brake line.

 

New oem cps

 

Full tune up, cap, rotor, wires, plugs, fuel filter

 

All new vacuum harness, replaced leaking vacuum canister from passenger fender, relocated it with shorter new vacuum lines

 

Checked tps and iac, had another comanche around and threw those on there to see if made any difference. I haven't done tps adjusting from cruiser tips yet, it's on my list...

 

Replaces egr with oem new egr...

 

 

I let it prime for 3 seconds before cranking, helps a little, but still have issue.

 

 

I plan to order volvo injectors, do the cps drilling trick from cruiser, and finish ground work from cruiser tips in the harness, and adjust the tps..

 

Also, it does idle a little rough. Not bad, drives great, but I can feel idle drop a little and come back u0, maybe 50-100 rpm... again, don't think it would ever die, just a slight stumble and recover, for like 1 second, only at idle.

 

Thanks for help!

Link to comment
Share on other sites

  • Replies 140
  • Created
  • Last Reply

Top Posters In This Topic

"Cranking" means the starter motor turns over the engine. It sounds like what you are talking about is "firing up," which is when the engine starts and you no longer need the starter motor.

 

The Renix system is characterized by a long crank period. The reason is that it's a comparatively "dumb" system. It doesn't learn anything from driving, so every time you start it, it has to re-synch before it fires.

Link to comment
Share on other sites

Sorry, I meant firing up. If I let it set for 2 days, it fires up everytime in 2 seconds...

 

If I try to crank within an hour or up to the next morning, it's like 7-8 seconds.

 

Why would it learn faster on initial fire up after sitting two days?

Link to comment
Share on other sites

So I have an update... I let it sit just now for 6 hours and it fired right up. 2 seconds, because of renix, and it was running great...

 

So it's something about when it's warm, not cranking well, or take like 7 seconds to crank...

Link to comment
Share on other sites

Question about #3, cleaning all connections. Do you just unplug and spray with cleaner or should I be scrubbing them or scraping then somehow also? Also, how long do you let then dry before plugging them back together and trying to fire it up? All the cleaners have warnings on them.

 

I started this weekend, did the front drivers relay and fuel pump connectors on that porcelain block up there, many more to go.

Link to comment
Share on other sites

I see in your writeup to brush the connectors. I will get a toothbrush or something. That's easy on the relays and some of the connections, but not so easy on others. I will just get a small flat head and so some scraping.

Link to comment
Share on other sites

I see in your writeup to brush the connectors. I will get a toothbrush or something. That's easy on the relays and some of the connections, but not so easy on others. I will just get a small flat head and so some scraping.

Toothbrushes are nylon -- much too soft to scrape through crude and corrosion to get down to clean metal. Go to Harbor Freight Tools and by a set of small, metal brushes. They're about the same size as a toothbrush, but mucgh more effective.

Link to comment
Share on other sites

I read all that, lots of the same stuff I'm trying, we seem to be on the same path, we will see if we end up in the same place...

 

I fixed my idle finally like 6 months ago but it was just a combination of everything that was said in my ROUGH IDLE topic.

 

...Clean grounds, upgrade ground wires, re-solder ground connections, ohm out wires for bad connections, voltage tests on certain sensors and relays, made sure I was getting good fuel pressure, upgraded my injectors, cleaned throttle body, made sure of NO vacuum leaks, replaced my intake/exhaust manifold gasket and made sure bolts were tight...

Link to comment
Share on other sites

I'm still having some cranking issues.  I made it through cruiser tips #1, #2, #3 (about half way, but all relays), #4, #5, #6 (looks good, need to solder them, but no lose connections), #7, #8 (TPS was out of adjustment, got it perfect), #21 (added a new OEM nos EGR), #22 (all new vacuum harness, new CCV, new vacuum canister, all new lines), #23

 

I also checked intake/exhaust manifold bolts, some were lose, tightened those up to specifications...

 

it is still hard to fire up when if it's run in the past few hours...  If it's cold, it fires up pretty well, if you shut it off and immediately crank it, it cranks pretty well, let it sit for a few hours, it's hard to fire up...

 

I always turn key to on, wait until I stop hearing fuel pump, then crank, then wait for it to fire up.

 

I did test tonight, for the first time, after letting it sit a few hours, I turned the key on, back off, back on, back off, and back on...  So I primed it 3 times, and it did fire right up.

 

Does this mean fuel pump internal check valve is bad and letting fuel go back to tank and making it harder to prime?

 

If I was to get a new fuel pump and try, can you get that at parts store or do you have to find OEM stuff online?

Link to comment
Share on other sites

I'm still having some cranking issues.  I made it through cruiser tips #1, #2, #3 (about half way, but all relays), #4, #5, #6 (looks good, need to solder them, but no lose connections), #7, #8 (TPS was out of adjustment, got it perfect), #21 (added a new OEM nos EGR), #22 (all new vacuum harness, new CCV, new vacuum canister, all new lines), #23

 

I also checked intake/exhaust manifold bolts, some were lose, tightened those up to specifications...

 

it is still hard to fire up when if it's run in the past few hours...  If it's cold, it fires up pretty well, if you shut it off and immediately crank it, it cranks pretty well, let it sit for a few hours, it's hard to fire up...

 

I always turn key to on, wait until I stop hearing fuel pump, then crank, then wait for it to fire up.

 

I did test tonight, for the first time, after letting it sit a few hours, I turned the key on, back off, back on, back off, and back on...  So I primed it 3 times, and it did fire right up.

 

Does this mean fuel pump internal check valve is bad and letting fuel go back to tank and making it harder to prime?

 

If I was to get a new fuel pump and try, can you get that at parts store or do you have to find OEM stuff online?

Or your injectors are leaking when off. Get a set of 746 Volvo injectors from Programbo on cherokee forum. 

Link to comment
Share on other sites

 

I'm still having some cranking issues.  I made it through cruiser tips #1, #2, #3 (about half way, but all relays), #4, #5, #6 (looks good, need to solder them, but no lose connections), #7, #8 (TPS was out of adjustment, got it perfect), #21 (added a new OEM nos EGR), #22 (all new vacuum harness, new CCV, new vacuum canister, all new lines), #23

 

I also checked intake/exhaust manifold bolts, some were lose, tightened those up to specifications...

 

it is still hard to fire up when if it's run in the past few hours...  If it's cold, it fires up pretty well, if you shut it off and immediately crank it, it cranks pretty well, let it sit for a few hours, it's hard to fire up...

 

I always turn key to on, wait until I stop hearing fuel pump, then crank, then wait for it to fire up.

 

I did test tonight, for the first time, after letting it sit a few hours, I turned the key on, back off, back on, back off, and back on...  So I primed it 3 times, and it did fire right up.

 

Does this mean fuel pump internal check valve is bad and letting fuel go back to tank and making it harder to prime?

 

If I was to get a new fuel pump and try, can you get that at parts store or do you have to find OEM stuff online?

Or your injectors are leaking when off. Get a set of 746 Volvo injectors from Programbo on cherokee forum. 

 

 

I agree.   I sent him a PM on 7/31, waiting for a reply, he hasn't been online since 7/30, hoping he gets back online soon and checks his messages...

 

I'm thinking about trying a CTS tomorrow just to see if it has anything to do with it, they are pretty cheap.  Will possibly rent a fuel pressure gauge to test that as well before replacing a fuel pump.

Link to comment
Share on other sites

Pretty sure this was a relay, probably the latch relay on the panel of 4.  I just replaced all 4 with new relays.

 

http://comancheclub.com/topic/47926-replacing-the-4-relays-on-the-renix/

 

So far so good, I drove it all day today, stopping for lunch, errands, etc...  She fired up after each time sitting.

 

It must have had no pattern and I just thought it did.  I bet the relay was just sticking most of the time and sometimes not.

Link to comment
Share on other sites

Try running some fuel SYSTEM cleaner through your OLD MJ (I guess that is what you have) a couple of fill-ups.  Most people would rather do valve jobs and overhauls  and injector rebuilds but this stuff actually works, to an extent, especially on OLD gummed up vehichles.

Link to comment
Share on other sites

I replaced all the injectors today with 746 injectors. I also put on a new oem regulator, and put in new ngk plugs gapped to 0.35. When checking the wires, I did notice one on the distributor wasn't pushed in all the way, so I might have had an issue there.

 

It's cranking just fine now, so far so good all day.

 

The idle is pretty perfect as well finally.

 

I do still notice when I first crank it and put it into gear and maybe rolling up to my first stop sign, the idle will drop low for about 1 full second or slightly longer and then recover back to steady idle.

 

It does it worse with the AC on.

 

It recovers and idles fine, but assume I shouldn't notice if all was perfect.

 

Done most cruiser tips, no vaccum leaks, manifold bolts tight, good compression, cleaned iac, adjusted tps, all updated grounds, soldered harness ground and ohms are good at sensors, all new vacuum harness, all new plugs, wires, distributor, rotor, new oem egr, new 746 injectors, new oem regulator, new brake line used for map sensor, new oem map sensor, new oem cps, new oem o2 sensor, cleaned electrical connections, cleaned coil connectors and bent out springs

 

It's running good, just seems like it's slower than it should be to adjust the idle.

 

I plan to check the the throttle stop tomorrow and then was wondering if it's a tps or iac going out or just how the renix is?

Link to comment
Share on other sites

I did, got it to a perfect .17 of the main voltage, ended up at .83, it was 4.83 x .17 was .829 so I'd did .83

 

It idea high when I adjusted when vehicle off like you said could haopen, so I adjusted while running and got it just right, depending on the accuracy of my volt meter of course.

Link to comment
Share on other sites

So went out again after it was sitting for a while and it fired right up. I believe along the way I fixed the cranking issue.

 

So with the engine kinda cold, cranked it up, idle goes up, slowly comes down, then it goes to where it should be, then it goes too low. I put it on gear but never gave the engine any gas. The idle stayed pretty low, towards the bottom line, enough to make engine rough.

 

I started giving it gas review it up and letting off, the idle then stabilized more.

 

So it's worse if you just never give it gas.

 

Also, sitting in driveway listenig, I noticed that while break pedal depressed there is a constant hissing sound, and I've thought my pedal was soft. I thought I tested booster by pedal being hard when engine off, and gets soft when you crank, but it sounds like a vacuum leak with your foot on the pedal, might be not related.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share


×
×
  • Create New...