Symptoms of bad head gasket

[Billy Mild]

My car has been running pretty good minus a slight hesitation with opening the secondaries when not fully warmed up. Once fully warmed up they seem to open up normally after I have gone WOT a few times. Its like they are almost sticking, but I heard lazy O2's can cause this. Will be replacing after my header swap.

Now to the serious issue. Lately if I drive my car for say 30 minute or more then go to shut off the engine and re start it a few minutes later it runs really rough. Almost as if one of the cylinders is misfiring/not firing at all. If I rev it up a bit, and start to drive the engine seems to run fine within a few seconds.

I remember my old 96 Neon when its headgasket went out behaved similarly except when it would run rough, it would continue to run rough until it completely cooled off. The ZR-1 isn't exactly doing that.

What are some of the symptoms of a bad head gasket?

[A26B]

That's a symptom most usually associated with a leaking fuel injector

[Billy Mild]

That's a symptom most usually associated with a leaking fuel injector

I replaced all the fuel injectors almost 2 years ago. They are the accell brand. At the time of replacing the injectors I also changed the fuel filter.

[We Gone]

Find someone with a scanner that has diagnostic capability. They will be able to check the 02s and lots of other things before you start throwing parts at it.

[Billy Mild]

Find someone with a scanner that has diagnostic capability. They will be able to check the 02s and lots of other things before you start throwing parts at it.

I have a MT2500 available in my toolbox.

[We Gone]

I have a MT2500 available in my toolbox.

Check the cross counts of the 02s. I had one that was very slow and caused a small hesitation.

[Hib Halverson]

Find someone with a scanner that has diagnostic capability. They will be able to check the 02s and lots of other things before you start throwing parts at it.

Actually, the right way to diagnose a potential leaking injector is to run the fuel pressure tests in the Service Manual. For that you need, obviously, the FSM for your model year and a pressure gauge appropriate for checking fuel pressure on a GM port injected engine. The gauges can be had from a number of vendors.

[We Gone]

Actually, the right way to diagnose a potential leaking injector is to run the fuel pressure tests in the Service Manual. For that you need, obviously, the FSM for your model year and a pressure gauge appropriate for checking fuel pressure on a GM port injected engine. The gauges can be had from a number of vendors.

Was just referring to checking the o2s

[Roadster]

.

What are some of the symptoms of a bad head gasket?

In my experiences with blown head gaskets is that you will see a ton of white smoke coming out the exhaust, as all of the fluids are now mixing together. You may or may not notice a significant change in performance under normal driving conditions. I have not experienced this in any car that I have owned, but have had this happened in some of the big trucks that I have driven over the years.

[Billy Mild]

Today was probably the worst it has been. I drove the car from work to the gym, roughly 30 minutes driving time. Vette ran great. Pulled well on the highway nothing a miss. The car sat for about 30-35 minutes outside. When I went to start it up, the idle was very rough and pulsing up and down, like it was hunting to find the idle. I didn't touch the gas pedal and let it stablize by itself. It took a 30 seconds before it idled at 1000 RPM's.

I haven't changed the plugs or anything yet. When I hook up the scanner what should I all be looking at?

[W i l l]

Probably would be quicker to shut the car off when it starts to act up, pull the plugs to see if one is wet from a leaking injector. Even a new injector can go bad.




I haven't changed the plugs or anything yet. When I hook up the scanner what should I all be looking at?

[Billy Mild]

Plug
https://lh3.googleusercontent.com/ap4-G8OmUcj81ehuG-O3-TTLdJSx7mV_PNQWiKv__8ge-mm-FgMniXoTX57LCX7n7hNvTah4ZPai_Wx1kQRU7ojJT7DdbEsgRI jTXOO8RwBFXE_c_0pPUoL-cavoRFGGhmbVNh4e0kCcNG2a7M8gz3kfC-yexrHwzIcSXOUyi8DuupGMKOGWhnuxeH1I7ObyhVVHGyLa4lRT vlRgN5dTNTRqP2azR0vb4R_Mf9Gl2A_79LBuwYbTVNKtPtdR0K wqJzYLaUikCpMR3Mz0gjGMmzz4XDCYb3oCjb9Six3R2uiDx4mz ia9c7YsaPdl_7aIclNPTPmub3APBNhI7nkDUyPdc57j5NzulEj goAv7EIFR2figBSjwJ2XlHFgcx6Ofap9sZbOY0yRnKZGb3J5Kr tAk3mpr0B_BfMx32Re88FaFXG0WmvcxFvxgcFzKOy1mTv4xzUi i6o3U9IenDUQ5hlyRIDoeAaiScYjioFnlC-e824pOC4B4x56nE_yrx6M9o-g1bQWLKYfNzg_6ZpUQMByJBD4qR2liEFSc_WcfCF2FyTgaBRAk 7HoIIciAVODSfAapk=w493-h657-no
https://lh3.googleusercontent.com/tQYVstcfEpn1BHYwSYuypAaJs8O8ypm-G15keqpiRbZ1zdVHIHGB8HYGysWY1hIb_gieBOIsdDz0T4FLwf C72fOHoLg4xTQxqQAx7mBtSf3MgjSwmVID-KmkoQBb_-BD794fkKrxZaqGXE9nd-purNoNsASfaoTGnKQ1d3moML-iiPNmCBVnHS9kpfl94VvWtHzA6aEUusNbvDf1IpGPLyZGr32aE jron_rhtPdp00jqJ1Fgrkzd3cQRyziSOzQXgvhEzSVRTR-d2Jg8DsqVt_1aP6VnApOYM7oxGRV_lF1JpAPD-5deAiQmDhAyGJvd9C1hr2MTE3_K74CvWDPpzJkchH4Tb_cpqv8 AmWkcLP2YuO_8UeLRlJtcPBjeNH0tEEEK3m0heVzF8szhJwMdI zwPb5wPCgjiivSYDqe2KUVie_IicFGCRSneacu3Z1qUsk9hk-3oZl4RGCD0gApNMWvvqkUI5cmlX3rzoU1VuI1qG2EElW4C7GoI YYPA3s25OXYhDwoREtW3kFLURW52hgU8k-TpYxCgLDU1a3CzujMseNYhtCRGDJInrbeLKO8e_lN_=w876-h657-no

Scanner
https://lh3.googleusercontent.com/E3GHQZnblwUxSbo00UOhf5masoZcfJ7zbOiIMzJC8MPb04dIpL f8616EmZhH-nhofGgPxaswKWxe0b3ZihbePmZ_F9zCGDwy_SNo2agyL3yjq1_ MsoA2duKz-oTPteWVYOaajBthK7y9L9X1qsZ5IEirQHNs8Ky5oxZgKRdUcEp l1bdvz-m-IN3N0jKPCVsPzHxyTMjqNQDZD2t1zD7NwZAqzMCWSenqf6MI9O vwm0NJz8651ioFAVlrhdYAttxHcHl08sH-E8dO5mOOMpz9-8l3GxPwCLQSdvvtCKVULND-dXAmeVSeftMKH_E86OxtGG4yNq8YPppgALrAB-kc2G-ycyH1fWKx1BJ_Dv5o9irxpJRTTTs9E2xwOMevQVbZp1M32MfvB Isfdg72lQgKdEmiRt271EuRBqeH6tIwPqJ4oo6xOxdYuExHvaQ sWcRrVlYgvBnCkL0IX83FTtNa0pX1XhM6WGaXOP1jnc0Mgt4Ai e8NMfbmvhl39rRzwealf9X08S5o3yA-HumV9iWRxXTFl-d-F0JPfDLq4oHdFcU-x8z8jLH1DyMLHbV9DyKGoWo2=w876-h657-no
https://lh3.googleusercontent.com/oJsahJV64BTr7eQYwMEkLCUzA27_Q5Kf9QPcje8wXogboIZgEm x4_iK2CUnn3nI-0B6-bumSibic8qB7B2J2HAgTNKvckor8T7XigOJmMvwNKlM2CSLyCe kZhG6kCHzwoSGxl7Oh6uMXDj0AXujWkrXMDSAbU80x-aB78ZxOJyAx2jK_30X63QrNKHzhNwLidLAf_c0qHg8Y-8X6-UOf9ZFggV1qy55yaPbuulyPocbX4jcg9QHkrLX8YV8S35-YUCKxeGxkH2BQRO0t_Yiffd4EdZf6Al7cSlXCXJnrdEJqoIYXX 9uCutjynMkdZ5jyw2ZCI4IAvpVDzaltNrkD2nq2WfB0tIS4BQo AkY3A3M-xr278E-3p0qxuRWW1pQq_ue2k5jAgqrPr4X5sg_WtpkqyqETqYU5GejG1 JxeqTZesoqvg4vGYPq8kt7EuS2VBla6bB2T1AT5zzP4wGZy7Ls NWQxmMXfR9dpKzVDKcFyUGAWQSp2R0rbinvlCbcS91YMSxp981 KUe6Btq_1ONYrLnAKr7v7EIDalF9BfhrT-Mkv7MPsMWGW2y5ItNSaMv4N14e=w876-h657-no
https://lh3.googleusercontent.com/PkjkjZIfz8HLWbqFHFh0eVxemtRnYQoElSdy54DBlLrnA9QIu4 WyrPkNFQWVt9li-PsCs64QOhHm3mqDiLpe2AiLBe0i2Q-l0nkaAOSe1HpPcbN-9bSLCdBEGtlpgNJOvdzwAz8k827rCx4eFzOQ0KSF4yapCkx_Iz rYtwQZgmxMnMp33aAhtV12CCW5xokRH8WnH5IMhz5Eu5Rb3dym YA4Ks84zp7Ax1pf5M8Uxr25qyVK7Khy_Cd26a5Yh29WO4IXWmx mYhZvJd2DENtMDdP536K0dwmCVviaCDUZ4RiSRltmgEngex6Ni kkuZPbU3BvOuwR2ofw16gbfJJBIYXT-DJugbHbmTXIw7UbtCpWVuWNFfbUptWNAEUL4xi5CSCXwxvBaV-xGMWEn9N71RyrqZ2MJKsjxcjvTLCCGvEEvSB1R_djLsueYRX-F43V9-tebI0ucD3RsgdeEdpN4Bbk8iPGD7xbPlmZsp3NGFCuBUv0vHeN 8fsT17jwQmvzpBj7SX-cSJXfmbZw4OMUKfYc1DpdJfKtxyl67nLqs8gWQywZrxU4DrDHf 7JS8T0eqglY5L=w876-h657-no

I don't know what the BLM numbers are, but they are different from side to side with the engine warmed up. O2 sensors look about even as well.

These screenshots were taken at idle. The spark plug looks pretty decent. Thoughts on the color of the plug? It is white on the grounding strap.

[Billy Mild]

https://lh3.googleusercontent.com/0Co3eK_UQ8j41uGVdI_-k6v9Ovjcjm44jgDbQpdz4Xa5D-h-OyXnr3jkYjrbZEzSVeHqPNih9eZcjNM7FkpQWtimEGkQ-SpcTWSUdCR05M7Keeo-5gRRDilH5D-HZNxQYpSgMXT65EqydlktLraeC7XkQa9JUjFxai078sRD6eTNg 0Sn1MDiSzvpQNInwoyjhTvdtK73IsJjMfh9gGCJURboRTWWezn ynlRn861RAsCtfRMQhRPx7k2SjMYhuzmhrgQYrQAgV5PCunK4X MKIhwpyFCjhtnKFAmhSQnyUpwrv8Uw-kyeoB5NZ3k_CfOjezv4yWxOvZW0dtf94YcIaaaOTBHN5wbVnRZ dhmQRJTWSxFVMjyx2PA0mUWpK4TCr7qqQzSxVyrpMjKFs8zF1g jZaEaLBBkDcVBEcjZ_HhqKJK0W4ZRn1VI1NHmCnc5ZYWiVCVEv TeDfgGj11HEA89wHJE_QrUbWoMVSanJQbMX1qgtFEyiNirDa0S fmMcMWQcSOsoQIoHorK7hFYBMPKhLojVVPz9LjyhMRAqYrw8uO TcHB584bzRVfhVQy7_BfuSGk_w=w1087-h816-no

https://lh3.googleusercontent.com/TjAE8RhD1PKSxzFjiiUE-s3niJgzTbM4PSs20diMMiuVUw9VXhvn-cQ2n6PU_0HXkKeTeuZOXsYK-D2TVbE21NuX3G3dYONLC2xJXHFJim4OVIdxHoxR8Cp-Ja9_sDYV9HJyJu_fbPu0JM5x9HxxJFMmHiTyBAZJalmKCa85yA 9Iozvgp4ZEWuX_HQSNdi7o7Pf0l4I_RehWybzz1JP39zFVZXxZ u8MaLroN5rOxMC-X9Jgsq9ZRzpNaOu-BpieYS6arTAHSnQJoRKVPpHn1hF_hr5auAFOROjQnpZwUUQGFd eCd610HDC278AAvhLSspwCFH9fvyKB_8_emwqO5OylH2XIVvDD lxQ3tSBHERDq1vVDJHrqrOZw6qzqWYaR34E4BqfMRpPp9iDYqw kBxIljKHpTwTO5MQ4yinzdvMgbJ0DP6PgnGcB4_ulydDn6VWLq Py39hx2vrAVZnk1sB3vDLfOA3AsLeJiSsyAS80pR-wu6imUO9IIJDtknWN0ML4t-l_NVYuW6ldCR5bCx-TNOY3d39bTASdJ4oK1STfCgMdpBSdvtXTEGIf3S6TtkamxMb=w 1087-h816-no

Any idea what BLM is? My idle is always above what the "desired idle" is for the chip. I noticed the only time my Idle Air Control is above 0 is when I actually am blipping the throttle. Could this be a reason my car idles higher than normal?

[rkreigh]

one thing to try (look a Haibeck site for procedure)

run the car until warm and ohm out the injectors through the wiring harness

they should be even and up over 10

if you see some low Ohms, chances are that injector has gone south and isn't flowing right when warm.

for head gasket, you can pressure check the cooling system and look for any signs of water in the exh or oil.

exhaust might smell sweet too, that's coolant!

LT5s are a bit known for HG issues, but usually "you'll know it"

[Billy Mild]

http://www.zr1specialist.com/HAT%20Web/articles/Measuring%20Fuel%20Injector%20Resistance%20with%20 the%20Plenum%20in%20Place.pdf

I'm assuming this testing procedure.