temp guage reading and pinging, oil pressure spikes?

[crustodd]

Hey Jeepers,
I was curious about something. My temp gauge registers a reading around 212 degrees on average. Sometimes it'll go up to around 230 if I set for a long period. It cools right down to around 200-205 when I am in motion. I have about 2200 miles on my 4.7now. It pings under 3/4 to full throttle, so I know it's got a few kinks to address. The weather has been around 40-50 degrees here in Oregon. I am wondering if, because of the temp. gauge sensor location, if the temp that the computer is getting would be the same? The temp gauge sensor is at the back of the head, the coolant temp. sensor is at the front. I know the computer works best if the coolant is around 195-200. I'm wondering if the temp. is showing 212 average, could that be part of the cause of the pinging? Would the computer be reading a high temp. and leaning the mix as a result, makin' it ping? If the temp. is showing 210 on the gauge, would that be the same temp. that the coolant sensor is getting? I'm gonna try cooler plugs and relocating the AIT sensor to the AEM air filter I picked up. Hopefully that'll help. Also, I have the Hesco high volume oil pump. When the oil is cold/cool, it spikes pressure up to 75-80 psi under full throttle. When it's totally warmed up, idle pressure is around 25-30 psi, but spikes to 75-80 psi under full throttle. I'm running Valvoleen 10-30 right now. I may try some flavor of 5-30 on the next oil change. Anyone using the Hesco pump and having this happen? Could it be because the engine is still new and tight? I'm hearing a little valve train rattle when it's cold too. Do the valves need to be adjusted during the break-in miles? 0-5000 miles?

Thanks

[jsawduste]

Hey Jeepers,
I was curious about something. My temp gauge registers a reading around 212 degrees on average. Sometimes it'll go up to around 230 if I set for a long period. It cools right down to around 200-205 when I am in motion. Normal I have about 2200 miles on my 4.7now. It pings under 3/4 to full throttle, so I know it's got a few kinks to address. Yes it does The weather has been around 40-50 degrees here in Oregon. I am wondering if, because of the temp. gauge sensor location, if the temp that the computer is getting would be the same? The temp gauge sensor is at the back of the head, the coolant temp. sensor is at the front. You have it backwards. ECU reads the rear sensor I know the computer works best if the coolant is around 195-200. A bit higher is ok I'm wondering if the temp. is showing 212 average, could that be part of the cause of the pinging? NO Would the computer be reading a high temp. and leaning the mix as a result, makin' it ping? NOPE If the temp. is showing 210 on the gauge, would that be the same temp. that the coolant sensor is getting? I'm gonna try cooler plugs What plugs are you using now ? and relocating the AIT sensor to the AEM air filter I picked up. That will work. IAT is the proper term Hopefully that'll help. Also, I have the Hesco high volume oil pump. When the oil is cold/cool, it spikes pressure up to 75-80 psi under full throttle. When it's totally warmed up, idle pressure is around 25-30 psi, but spikes to 75-80 psi under full throttle. I'm running Valvoleen 10-30 right now. I may try some flavor of 5-30 Good idea on the next oil change. Anyone using the Hesco pump and having this happen? Yes Could it be because the engine is still new and tight? Doubt it I'm hearing a little valve train rattle when it's cold too. Do the valves need to be adjusted during the break-in miles? 0-5000 miles? Not sure of your set up so no comment
Thanks

[gradon]

Right now, my 4.6 w/ 10:1scr&8.57dcr needs 93 octane to prevent pinging b/t 2.5-3.0Krpm. I'm using a HV melling oil pump and psi is b/t 60 cold, 25-30 warm idle and 60-70 warm w/ load(2.0-3.5Krpm).

[Mgardiner1]

If you stuck with hydraulic lifters then your valves never need to be adjusted. Even if they did, there is no way to adjust them! If you are using adjustable rockers, but still retained the hydraulic lifters, they will still never need adjustment, unless they were not set up properly from the get go.

About the two coolant sensors..... I dunno about you guys, but the single wire sensor on the back of the cylinder head (closest to the fire wall) is what my temp gauge reads, and the ECU reads off of the 2 wire coolant sensor in the thermostat housing....

[SilverXJ]

About the two coolant sensors..... I dunno about you guys, but the single wire sensor on the back of the cylinder head (closest to the fire wall) is what my temp gauge reads, and the ECU reads off of the 2 wire coolant sensor in the thermostat housing....

That is correct for all Jeeps with the dual sensors. The one for the head goes to the dash temp gauge, the one in the t-stat housing goes to the ECU.

[jsawduste]

About the two coolant sensors..... I dunno about you guys, but the single wire sensor on the back of the cylinder head (closest to the fire wall) is what my temp gauge reads, and the ECU reads off of the 2 wire coolant sensor in the thermostat housing....

That is correct for all Jeeps with the dual sensors. The one for the head goes to the dash temp gauge, the one in the t-stat housing goes to the ECU.

Yep I screwed up. :doh: Just this morning I rewired my harness for Autometer gages. Put the new sending unit up front. :boom: A bit of solder and some heat shrink tubing.
All fixed now.

Tomorrow I`ll do it right. :worship:

[1bolt]

Yeah sounds like you have issues to address... I would replace the T-stat with a 185* check and flush the cooling system and if still not reading below 200 I'd check the gauge, against an Autometer gauge. Then check for coolant traces in the oil with an oil analysis not that I really suspect a trace HG leak but for 20 bucks you can eliminate it from contention with a oil analysis... A fresh new coolant sensor follows this up (as everyone else noted the one on the T-stat housing).

Note this is just how I'd do it, in order of EASY and CHEAP first.

Still cheap but less easy, make sure the cat isn't plugged up (cut it off look through it making sure to turn it and shake it enough to show any broken honeycomb) and then use a couple adapters to muffler clamp it back on)

Now if none of that does it I'd turn to thinking about fuel mixture... Home made adjustable MAP comes next. Then spending really starts to happen. A new o2 sensor.

Next I'd get a wideband Air/Fuel. It's expensive but usefull for more than just this problem and if you got this far without fixing the problem it becomes justified as a diagnostic tool to keep you from pinging your engine to death.

If the fuel mix is good and you correct your WOT ping with the MAP (it should work) but still have over 200* running temps then it's on to the cooling system again. The radiator and new water pump.

[crustodd]

Hey Folks,
The plugs I'm currently running are the Champion RC12LYC. I'm gonna try the cooler RC10YC4's or the NGK equivalent. The cooling system is all new. Hesco H2O pump, new radiator,new heater core, new silicone hoses, new fan clutch. My stock '99 Grand Cherokee runs about the same temp. I'm running 92 octane premium all the time. I'm gonna' call Bernie at Hesco about the oil pump. It pegs the pressure gauge under full throttle, but goes right back down when I let up. He explained that those Melling pumps are set for 80 psi stock , but that they adjust them down to 45 psi, I think, when they blueprint them. Seems odd. It's been running oddly it different ways lately, though. When it's cold, I get about 5 seconds of lifter noise on first start up in the morning. Like the pressure has bled off. When it's warm, the engine revs up to about 2k rpms on start up, then comes right back down. Today , it was doing things similar to when I had a bad TPS, which I replaced about 6 weeks ago. I'm takin' it to Unichip for the chip and tuning in the next 6 weeks or so and I think some of the erratic running will be solved by that. This is an OBD 1 engine, but it's not throwing any codes.

More thoughts?

Todd

[crustodd]

The coolant sensors are both new too.

[crustodd]

Oh yeah, o2 sensor and hiflow cat, new within 10-15K ago

[Mgardiner1]

If i remember you had a stroker built for you that did not involve extensive machining to get a tighter quench, right? What cam did you go with? Did your engine builder install your pistons backwards which would cause the quench pads to be on opposite sides of the combustion chamber?

Also, have you gotten other opinions on the noise? I only raise that as a question because when i dropped my stroker in, i installed a Centerforce Stage 2 clutch. And it has those little "flyweights" on the clutch fingers. Let me tell you those weights are noisey as hell, and i'd probably have gone with a different clutch had i known they'd be that noisey. I mention this because it sounds really close to engine "pinging". I know its not detonation not just because i can tell the difference, but because it happens on both acceleration and decelleration.

[crustodd]

Yes, I did have this engine built and the guy who did the work has lengthy experience and was very aware of what we were try to achieve. The block was zero decked, the head was milled a bit to get the chamber volume to what I wanted, and I used the KB 21.73 dished pistons. The cam is the Lunati Voodoo, 73501, I think. It's the "stage 2" of the AMC six cylinder cams. I don't drive it WOT very much either, so it's not pinging constantly. I have the AW4 auto, so it's not clutch related. I have some 110 Sunoco that I may try adding in. 2-3 gallons to a 1/2 tank and see if that changes things. If it's running lean though, wouldn't it still ping?

Todd

[SilverXJ]

Yes, I did have this engine built and the guy who did the work has lengthy experience and was very aware of what we were try to achieve. The block was zero decked, the head was milled a bit to get the chamber volume to what I wanted, and I used the KB 21.73 dished pistons.

If the machinist went off the sheet that KB sent with the pistons there is a good chance that the pistons were installed backwards. The sheet they send is wrong opposite what it should be.

[SilverXJ]

When it's cold, I get about 5 seconds of lifter noise on first start up in the morning. Like the pressure has bled off. When it's warm, the engine revs up to about 2k rpms on start up, then comes right back down.

Todd

This lifter noise, is it the same noise you mentioned in the initial post? Does the sound go away after that 5 seconds or is there another sound?

As for the temp the 212* seems correct, but the 230* when sitting for a while isn't normal.

[crustodd]

Hey Silver,
Yes, the rattley noise is what I originally spoke of. It goes away when the has run for a few seconds. I think the guy who put this together is pretty sharp, but I'll ring him up tomorrow on the piston install. He understood the quench issue VERY clearly and we got the quench to right around .040-.045.