Motor sounds like a diesel engine

[NISSAN240SX12]

This is my problem, I just finish doing a complete rebuild on my ka24de. This was my first major build ever. The car starts right away and idles at 700rpm. but when it revs up it sounds like a diesel. I have checked and rechecked the timing and the alignment of the cams. Its all correct. Its set at 20degs. The car doesnt have the power as it should. I just replaced the battery and low and behold it goes crazy. The car is bogging out when i hit the gas. when i step on the break pedal, turn on the heat / a/c, turn on the lights, ect... the heat gauge shoots through the roof. I dont know where to start to search for a problem like this? have any of you run into a issue like this at all. any help would be great! thanks!

[modulation]

when i step on the break pedal, turn on the heat / a/c, turn on the lights, ect... the heat gauge shoots through the roof.

Like the engine actually overheats or just the gauage?

This one problem sounds like an electrical short.

[rogoman]

Looks like you've got several problems. First check all the engine wiring connections; in particular the engine grounds.

At higher revs, the dieseling noise could be extreme detonation due to a super lean fuel mixture or maybe you're misinterpreting the noise as rod/main bearing knock.

Check for a major vacuum leak by using a vacuum gauge connected to a full vacuum source; the reading should be around 20 InHg at idle and higher revs.

Check the oil pressure by installing a temporary mechanical oil pressure gauge. You would remove the oil sensor which is located next to the oil filter and install the mechanical oil pressure gauge in it's place; you may need to get an 1/8 BSPT to 1/8 NPT adapter to hook up the gauge. With the engine fully warmed up, the pressure should be as follows:idle - at least 11 psi3000 RPM - 60 to 70 psi

[Vegascorbin]

I agree with all of the above, exspecualy the ppoint about checking the grounds.

Did you paint the engine while it was out? Did you clean off the paint from where the grounds connect?

Double check that you connected everything and let us know.

[NISSAN240SX12]

well I have solved the grounding issue. the car is running 10 fold compared to earlier. the voltage is stable at 13.4 volts now. I installed four 4 gauge wires for grounding. I cleaned the MAF. Changed the fuel filter. I have replaced the oil pump and oil strainer, but i wouldn't think that the oil pressure could be an issue. but you are right i need to check the psi on it. the dieseling noise is not terrible but when at idle it smooths out quite a bit. acceleration is still slugish. at times when i give it full throttle its starts out slugish and at times it clears up and goes back to being slugish again. so I know there is something i have missed here. thanks to you all for all your input!

[NISSAN240SX12]

I have checked the ECU for any codes that could be throwing off. It read off three codes 11, 21, 33. Code 11 was the position sensor so I replaced the Distributor. I checked the ECU again and code 11 went away. So I'm down to 21 and 33. Code 33 is the O2 Sensor. I put a volt meter to it and its reading 1.03 volts and I know it should be about .05 volts. The sensor is new so I think my cams are off. If I retard the distributor back a bit back to TDC while its running. The Diesel like sound goes away. I checked the manual in regards to the O2 sensor and it tells me if the sensor is reading 1 volt its running to rich. The book says it indicates that there is little oxygen in the exhaust. So I'm thinking that maybe I need to adjust the Intake Cam over one tooth over clockwise. What do you guys think? I just don't want to *uck up my valves..... As far as code 21 goes I'm not sure about that, it maybe related to this whole problem. If its the ignition coil i guess i could get on and see if that helps at all but it was working prior to this rebuild. So again not sure...... Thanks all for any input!

[NISSAN240SX12]

i just rechecked my timing again and its correct and also checked my cylinder compression. cylinder 1 reads 145 and the rest follow 135, 160,160. so its not very consistant. i put a vacume gauge to the engine and it reads 15hg. but its stable at 15hg.

[s13-t]

how exactly did u do the compression test? motor should be warm. eliminate fuel and spark. hold gas pedal all the way down and crank 5 to 7 times. assuming u did it right... the 145 then 135 then two 160's would indicate that cylinder 1 and two either have bad rings or the valves arnt staying closed. i could be wrong. my sr20 sounded like a desiel for a long time then the head started to rattle. the rattle got so louud upon acceleration that i couldnt hear the turbo spool. so now the car is sitting till i figure it out. im assuming a lifter or rocker problem. too be on the safe side try not to drive your car too much until the problem is found and fixed.

[rogoman]

i just rechecked my timing again and its correct and also checked my cylinder compression. cylinder 1 reads 145 and the rest follow 135, 160,160. so its not very consistant. i put a vacume gauge to the engine and it reads 15hg. but its stable at 15hg.

You've got a big problem with the compression readings. The compression should be at a maximum of 179 psi and a minimum of 151; differential limit between cylinders is 14 psi. There could be several reasons for this:- Motor not fully broken in.- Cylinders were never honed.- Rings installed incorrectly.- Insufficient valve lifter clearance.- Leaking head gasket.

A vacuum reading of 15 InHg is not good. The reading should be around 20 at idle and around 21 at higher revs.

[NISSAN240SX12]

well i just did and leak down test and it failed terribly. when i started at cylinder one it was not good at all right away. i can hear the air leaking throught the valve cover which sucks balls. so thats telling me that i have bent valves. this is getting depressing and im down to not able to fix this car. no money no car........... so i need to replace the head or fix it and its going to be expensive either way........ thanks everybody for all the great advise and help. I'm just going to have to hang the towel up on this one............this sucks