After my intake/exhaust manifold swap, I have a slow and quiet start every so often. The engine doesn't crank loud and fast, it is really quiet and when the engine starts the rpm builds to idle, instead of revving high and dropping to the correct rpm (if that makes sense).

I also noticed my engine is running hotter and i may have a slightly rougher idle since i can hear the slight hiccups in the exhaust and the engine shakes every couple seconds. It stays at temp when driving, but idling the e-fan kicks on after 5 minutes and I can't remember the last time that fan kicked on.

I will be doing a smoke test for my vacuum lines and will rent a gauge to test my fuel pressure. Is there any indication which way I should look before I can get around to these tests?

I am testing if my issue is fuel pressure related by letting the fuel pump prime twice before starting, and I haven't had the slow/quiet start the last few times doing that. I could have bent a fuel line but it seems to run fine so I am not so sure.

Back to the vacuum part, since I upgraded my intake manifold to the later model, would that make an old vacuum leak more noticeable and cause issues?

I do not have a vacuum ball and the line is just capped, my cruise control works far less often than it did before the swap so that leads me towards something going on. No visible codes yet but will have them pulled soon.

edit: Just remembered when I was having the temp. issues, my battery dropped to about 11v and as I turned the fan speed up for the heat, the gauge dropped another few volts, guessing around 7v? Efan was off, but headlights, wipers, radio, gps, and fan were all on. Just never have I seen the gauge respond like that.

Sorry this is a repost/lengthy post, I had a lot more info and new issues and the last post didn't get any replies.

Thanks!

 

A bit of an update here. I redid some vacuum lines I felt could leak and did a simple smoke test with cigar smoke. I found no leaks when blowing smoke into the intake and the hard line by the cruise control T fitting. I still have no vacuum ball and the system seems sealed tight. I have all sorts sounds I am not familiar with since my noisy manifold crack no longer covers them up, but trying to eliminate them. I used a piece of hose to check for anything strange and that valve on the back of the intake manifold is making a loud hissing sound but I see and feel nothing wrong with the pieces.

The engine fires right up in under a second in the morning when it is cool out, but when I leave work in the early pm I am noticing my starting issue more pronounced. Today it took about 5 seconds of turning over before it started. By that I mean the engine pretty much started, but wasn't up to speed enough for me to disengage the starter. I am leaning towards a fuel issue but I really don't have the cash to drop $150 to borrow the gauge from autozone.

Efan still kicking on if I idle for about 3-5mins also. Idle feels consistent, and no stumbling issues when driving. I may be struggling a bit when accelerating but I am not used to my new injectors/intake enough to know what is okay. No fuel smell at any time either.

 

As far as the cooling issue, it sounds to me like the clutch fan is bad. What is the condition of the coolant and how about the t-stat? Those are other things you should check.

Oh, and it sounds like your alternator isn't working either. Get a DMM and check voltage at the battery while it's running- should be around 14V.

 

I am almost positive the starting issue is related to a leaking fuel injector, after a few more hours of research. The injector is flooding a cylinder when the jeep is shut off, and restarting it immediately works okay, but if i wait longer than 10 mins to start, I have issues. The fuel evaporates overnight allowing for a flawless start in the mornings. After the jeep sat for an hour after shutting off, i pushed in the valve on the rail and no gas even trickled out. Primed the pump and listened inside the intake for fuel dripping but must be leaking in a way I can't hear like that. I primed it again and pushed the valve in and got an impressive spray, so I think I pinpointed the issue.

I will pull the rail soon and check for the leaking injector, but can anyone provide input on if I should just soak them overnight, or should I buy a rebuild kit with pintle caps, filters, etc? Anything else would be helpful too.

To the temp issue, the fan clutch when mostly cool spins with enough resistance that once I let go of the fan, it stops moving. There is no forward or back play in the fan. I never understood how the fan worked until researching just now, I figured it just ran with the belt and thats all. I have never noticed a difference in the speed of the fan, and it is always spinning really fast.

I did a full cooling system flush a few months back, and the tstat seems to be okay. Alt seems to be running up to par now, I think the strain of lights, wipers, fans, radio, and other stuff that night just was too much. Sits fine since then. The upper rad hose is hot after it sits a while after driving but well before the engine is to temp. pretty sure it isnt hot to the touch while driving below operating temp because the lower rad hose was cold when shut off/parked. I assume the top hose was warm because the tstat doesnt completely block off all flow, so enough can push by to heat the top hose.

Time to toy around with this fan clutch now!

 

It's kinda funny that you are having a simular problem that I am having. I can't say it's identical but read through my thread:
https://www.cherokeeforum.com/f2/doe...t-soak-142383/


I too have upgraded the intake and exhaust manifold, as well as switching to Dodge Neon injectors, and it's almost imossible for me to start the Jeep within the first hour after shutting it off. I am strongly leaning towards some sort of heat soak problem, but it's still difficult to say. After you read the thread let me know what you think. Thanks.

 

I know people mentioned it several times in your thread and you said you tested the cps, that sounds like part of your issue.

I have not had any issues after the engine starts besides it getting a little warm when im not moving. The fan seems to be in good shape and belt isn't slipping, so im lost there again.

If you have a leaky injector like I suspect I have myself, ours may show different symptoms depending on how bad the leak is. You could be leaking so much gas while running that it chokes the engine out, but you would notice the missfire and throw a few codes if it was that bad I think. Im heading to autozone now and will have them pull my codes, I have no CEL but I don't know if I can throw a code without the light being on lol.

 

Test fuel pressure look for injector leak down or check valve on pump allowing fuel back to the tank i have the same problem went through 3 sets of different injectors stock, 5.0 ford, and 5.4 ford ended up being the pump check valve change pump runs great

 

no visible external leak, and no smell of gas. I still have the issue if i prime the pump twice, and it starts fine after a long sit, and it was not an issue at all before my recent upgrades/fixes. Fuel pressure is fine when running but is gone within 10-30 mins of being shut off. pretty sure there is no check valve in our electrical pumps, but I am not positive.

 

I have extensivly checked the fuel pressure. What I did notice is when the jeep is cold, started, then shut off before it reaches operating temps the residual pressure drops to about 20psi in about an hour, where as when it was hot (my jeep never over heats and idles perfect) after I shut it down it will drop pressure a bit faster- to about 15psi in less than 30 minutes. Pressure always comes right back when I crank to start it. I have no strong odor of gas as I would if I had a leaky injector pouring fuel into a cylinder.

People keep suggesting the CPS even though it metered out okay when I was in a no start condition. I am not one of those people who spends money needlessly so I have not replaced it yet.

 

fuel pressure on mine would be around 25+ with the old pump im at almost 45+ with the new pump

 

it should be 45-49 while running, yes. Yours held that high after shutting off?

 

Oh no not after shutting i don't remember it was a while back but I think it was high what is yours at idle and at a rev?