160 therostat vrs 195. And Heat soak Check engine Issues.

[Phman9]

There is a lot of debate over 160 thermostat vrs 195. Ive ran them both and have several different issues running either of them. Let me start with my Engine build.
I sent stock 4.0 To Western Engine Supply, big mistake, I was told by western Engine to run a 160 Thermostat because strokers get hot. I followed the engine builders recommendation.

2001 Cherokee 4.6
Banks headers
Ported intake manifold and head
Stock Injectors
160 thermostat

With this 160 thermo combination, My Engine temps were nice and low, In hot Denver summer my gauge always stayed under 200 Degrees. After 10000 miles I needed a new CAM. 20,000 Miles I need a lower end rebuild, I have a main bearing noise. With all that said, for the most part the Engine drove well and strong until sudden noises developed.
I believe running a 160 degree thermostat made the engine cool but it caused MY jeep to run rick and break down the oil viscosity causing engine wear.

Because I thought maybe the bearing noise I heard was my water pump, I replaced the water pump and thermostat. I replaced the 160 thermostat with a stock 195 thermostat.
Now my temps stay at 220 like it did when it was stock. Over this winter i didn't notice any issues but as the temperatures have been rising, new problems are starting.

My biggest issue now running a 195 thermostat is HEAT Soak vapor Lock after a hot restart. The engine starts and runs strong, but if i turn it off and restart. I get a PO202 injector short code and the Check engine light flashes. The engine sputters and hardly runs. I have to wait hours until i can start with no issues.

Im going to toss in a 160 and trade this bitch in.
FOR sale 2001 Limited Cherokee 4.6. I'm done with it.

[SilverXJ]

They were wrong about the 160*

2, The common heat soak issue doesn't give injector fault codes. It gives misfire codes such as p0304, p0303, etc.. You may have a faulty injector. You also shouldn't be running stock injectors on a stroker.

[Phman9]

Ive checked all cables and metered all injectors with no shorts. Only happens during heat Soak,Runs great until i turn it off and start again. po303 is a common heat soak code but we don't want to rule out a po202 to the heat soak issue. I am aware of running stock injectors, this was a recommendation from western engine supply. 2001 stock injectors run 23lb/hr

[SilverXJ]

po303 is a common heat soak code but we don't want to rule out a po202 to the heat soak issue.

0202 has nothing to do with the common heat soak. Bad injector, bad wiring or bad PCM. Heat soak will not cause a short.

I am aware of running stock injectors, this was a recommendation from western engine supply. 2001 stock injectors run 23lb/hr

They are 22.5, but that doesn't matter as it will still run lean as the pcm is designed to use that size injector. You need larger injectors.

[Phman9]

Regardless of the norm, i am having this misfire issue only after heat soak. After changing to a 195

[Cheromaniac]

Im going to toss in a 160 and trade this bitch in.
FOR sale 2001 Limited Cherokee 4.6. I'm done with it.

Don't give up on it yet. I've been running a 180* t'stat for many years without issue and I think you could do the same. To cure the injector heat soak issue, you could stick a Thermotec heat barrier on the underside of the intake manifold. Simple and effective.

http://www.angelfire.com/my/fan/manifold.html

As far as strokers running hot is concerned, that's a load of horsecrap. My cooling system is stock except for a 180* t'stat and dual electric fans, and it's been able to cope with 110-120*F summers just fine.

[Phman9]

I plan to add some thermo insulation this weekend and try to track down this PO202 issue more. Either way I'm selling it off.

[JPrubo]

Well I hope you either fix fully or let the potential buyers know. I hate it when people unload problems on someone else.

[SilverXJ]

Heat soak causes air to form in the fuel rail and injectors. It will run rough for 30 seconds or so, then clear up. Possibly setting misfire codes. Air in the rail and injectors will not cause a p0202 code. Heat may make the true problem worsen and insulating the rail and injectors may mask the problem.

[Phman9]

Last night. I traced the and metered the injectors to the PCM looking for a short, again. All injector wires to the pcm are reading 1.7 Ohm. I am also getting 10V to each injector. The short only happens after a restart over 200 Degrees. When I started the engine cold last night, it started and ran strong, with no check engine lights. I turned off the engine at 140 degrees waited 5 min and restarted. Everything ran and started fine with no check engine light. After I get the temp over 200 I turned it off and waited 5 min and restarted. This is where i get the misfire and a flashing check engine light. After waiting for it to cool down it starts perfect with no misfire. The heat is causing something call it what you want its still a heat issue. I never had this issue running a 160 therm

[SilverXJ]

Are you getting any other codes besides the P0202 code? Maybe a P0302? What I would do is swap the #1 and #2 injectors and see if it moves. If it does (code changes to P0201)its the injector. Since your injectors are the wrong size anyhow it would be a good idea to replace them all. If the code stays at 2 its most likely not the injector.

Since the problem happens while hot you will need to do your testing while hot. Check injector resistance, check circuit resistance, use a noid light. Pay particular attention to #2.

P0202 means that the PCM detected a fault in the injector or the wiring to the injector. It monitors the injector and when the injector is activated, the PCM expects to see the voltage pulled "low" or close to zero. When the injector is switched off, the PCM expects to see a voltage that is close to battery voltage or "high". If it doesn't see the expected voltage the PCM will set this code. The PCM also monitors resistance in the circuit. If the resistance is excessively low or high it will set this code.

Potential Symptoms:
The symptoms for this code will likely be a misfire and a rough running engine. Poor acceleration. The MIL will also be illuminated.

The causes of a P0202 engine light code could be any of the following:

Bad injector. This is usually the cause of this code but doesn't rule out the possibility of one of the other causes
Open in the wiring to the injector
Short in the wiring to the injector
Bad PCM

Possible Solutions:
First, using a DVOM check the resistance of the injector. If it isn't within specs, then replace the injector. Check for voltage at the fuel injector connector. It should have 10 volts or more. Visually check the connector for damage or broken wires. Visually check the injector for damage. If you have access to an injector tester, activate the injector and see if it operates. If the injector operates, then you likely have either an open in the wiring, or a blocked injector. If you do not have access to a tester, swap the injector with another one and see if the code changes. If the code changes, then change the injector.

BTW, the common heat soak issue is typically isolated to cylinder #3 and #4.

[Phman9]

I am not getting any other codes. Swapping injector 2 over to 1 was my next test.

[SilverXJ]

Let us know what you find.

I was just thinking about your past bearing issue. It could be very well be related to using stock injectors, but I am not dismissing the 160* t-stat theory. Maybe you didn't hear pinging or it wasn't the very audible form. I know for a fact that the stock injectors with the stock PCM (no piggy back or tuning) are not compatible with a stroker.

[Phman9]

I believe you are correct. I believe the 160T and stock injectors are the cause of my CURRENT bearing noise. https://www.youtube.com/watch?v=0ZQtUC-zlN0
I followed the engine builders recommendation for 160 t and stock injectors. I questioned him 50 times about this set up. He insured me he has built hundreds of strokers with no problems. What I learned is that Western Engine Supply is total full of SHART. I never heard any pining. I was also told I could run regular pump gas. BTW nice arduino mods. Very impressive build SilverXJ.

[SilverXJ]

Damn. They really screwed you over. I wonder what the compression ratio and the cam is.

Its hard to tell what I am hearing in the video, but you should pull the covers off the bell housing and check the flexplate to torque converter bolts as well as visually inspect the flexplate for cracks.

Thanx for the compliments.